herbs

A QUICK GUIDE TO HERBAL SUPPLEMENTS

at a glance

U.S. Department of Health

and Human Services

National Institutes of Health

National Center for Complementary 

and Alternative Medicine
i

contents

Herbs at a Glance: An Introduction . . . . . . . . . . . 1

Herbal Supplements: A Word About Safety . . . . . 5

Individual Herbs

Aloe Vera . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Asian Ginseng . . . . . . . . . . . . . . . . . . . . . . . . . 10

Astragalus . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Bilberry . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

Bitter Orange . . . . . . . . . . . . . . . . . . . . . . . . 16

Black Cohosh . . . . . . . . . . . . . . . . . . . . . . . . . 18

Cat’s Claw . . . . . . . . . . . . . . . . . . . . . . . . . . 20

Chamomile . . . . . . . . . . . . . . . . . . . . . . . . . .22

Chasteberry . . . . . . . . . . . . . . . . . . . . . . . . 24

Cranberry . . . . . . . . . . . . . . . . . . . . . . . . . .26

Dandelion . . . . . . . . . . . . . . . . . . . . . . . . . . 28

Echinacea . . . . . . . . . . . . . . . . . . . . . . . . . . 30

Ephedra . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

European Elder . . . . . . . . . . . . . . . . . . . . . . .34

European Mistletoe . . . . . . . . . . . . . . . . . . . . 36

Evening Primrose Oil . . . . . . . . . . . . . . . . . . . .38

Fenugreek . . . . . . . . . . . . . . . . . . . . . . . . . . 40

Feverfew . . . . . . . . . . . . . . . . . . . . . . . . . . .42

Flaxseed and Flaxseed Oil . . . . . . . . . . . . . . . . .44

Garlic . . . . . . . . . . . . . . . . . . . . . . . . . . . . .46

Ginger . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
1

Ginkgo . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50

Goldenseal . . . . . . . . . . . . . . . . . . . . . . . . . .52

Grape Seed Extract . . . . . . . . . . . . . . . . . . . .54

Green Tea . . . . . . . . . . . . . . . . . . . . . . . . . . 56

Hawthorn . . . . . . . . . . . . . . . . . . . . . . . . . . 58

Hoodia . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60

Horse Chestnut . . . . . . . . . . . . . . . . . . . . . . 62

Kava . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .64

Lavender . . . . . . . . . . . . . . . . . . . . . . . . . . .66

Licorice Root . . . . . . . . . . . . . . . . . . . . . . . . 68

Milk Thistle . . . . . . . . . . . . . . . . . . . . . . . . . .70

Noni . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .72

Peppermint Oil . . . . . . . . . . . . . . . . . . . . . . . . 74

Red Clover . . . . . . . . . . . . . . . . . . . . . . . . . .76

Saw Palmetto . . . . . . . . . . . . . . . . . . . . . . . .78

Soy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80

St. John’s Wort . . . . . . . . . . . . . . . . . . . . . . . 82

Thunder God Vine . . . . . . . . . . . . . . . . . . . . . .84

Turmeric . . . . . . . . . . . . . . . . . . . . . . . . . . . 86

Valerian . . . . . . . . . . . . . . . . . . . . . . . . . . . 88

Yohimbe . . . . . . . . . . . . . . . . . . . . . . . . . . . 90

References

Standard References . . . . . . . . . . . . . . . . . . .92

Additional References for Specific Herbs . . . . . . 93

Index of Common and Scientific Names . . . . . . . 99

Index of Health Conditions/Uses . . . . . . . . . . . . 101

For More Information . . . . . . . . . . inside back cover

herbs at a glance:

an introduction

Many people take herbal supplements to boost their 

immune systems, treat allergy symptoms, prevent a 

cold—all in an effort to be well and stay healthy. There 

are hundreds of herbal supplements available in the grocery 

store or pharmacy or for sale on the Internet. And, there are 

many claims about their health benefits. How can a consumer 

decide what’s safe or effective? 

This booklet will give you a basic understanding of some of 

the most common herbs in popular dietary supplements—

their historical uses, what they’re used for now, the scientific 

evidence on their effectiveness, and side effects or cautions 

for you to consider. 

To manage your health, you need to be an informed consumer. 

Learn about herbal supplements and talk with your health care 

providers about everything you are doing to stay well. 

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Herbs as Medicine—

Now and Then

In the United States, nearly 

1 in 5 adults—or over 38 

million people—reported 

using a natural product, such 

as herbs, for health purposes 

in a 2007 survey. Among 

the top 10 natural products 

used were several botanicals 

covered in this booklet: 

echinacea, flaxseed, ginseng, 

ginkgo, and garlic.

People have used herbs as 

medicine since ancient times. 

For example, aloe vera’s use 

can be traced back to early 

Egypt, where the plant was 

depicted on stone carvings. 

Known as the “plant of 

immortality,” it was presented 

as a burial gift to deceased 

pharaohs. Lavender, native to 

the Mediterranean region, was 

used in ancient Egypt as part of 

the process for mummifying 

bodies. Chasteberry, the fruit 

of the chaste tree, has long 

been used by women to ease 

menstrual problems and to 

stimulate the production of 

breast milk. Cat’s claw, which 

grows wild in Central and 

South America, especially in 

the Amazon rainforest, has 

been used for centuries to 

prevent and treat disease. 

Hoodia, a flowering, cactus-like 

plant native to the Kalahari 

Desert in southern Africa, has 

been used by the Kalahari 

Bushmen to reduce hunger and 

thirst during long hunts. 

Herbs still play a part in the 

health practices of many 

countries and cultures. 

Ayurvedic medicine, which 

originated in India, uses herbs, 

plants, oils, common spices 

2

What are herbs?

An herb (also called a botanical) is a plant or plant part 

used for its scent, flavor, and/or therapeutic properties. 

An herbal supplement is a type of dietary supplement 

that contains herbs, either alone or in mixtures.

Did you know that some of our medicines 

are derived from plants and trees?

Drug Name Plant/Tree

Digitalis (heart drug) Foxglove plant

Paclitaxel (cancer drug) Pacific yew tree

Aspirin Willow tree

Quinine (malaria drug) Cinchona tree 

Morphine Opium poppy

Galantamine 

(Alzheimer’s drug)

Daffodil bulbs

Vincristine (cancer drug) Rosy periwinkle

Reserpine (blood 

pressure drug)

Indian snakeroot plant

(such as ginger and turmeric), 

and other naturally occur-

ring substances. Traditional 

Chinese medicine uses herbs 

such as astragalus, bitter 

orange, and ginkgo for 

various health conditions. 

Herbs are also an important 

part of Native American 

healing traditions. Dandelion 

and goldenseal are examples 

of herbs used by Native 

Americans for different 

health conditions. 

NCCAM’s Research 

on Herbs

While millions of Americans 

use herbal supplements, 

much remains to be learned 

about their safety and effec-

tiveness. The National 

Center for Complementary 

and Alternative Medicine 

(NCCAM) at the National 

Institutes of Health is the 

Federal Government’s lead 

agency for studying all 

types of complementary and 
5

alternative medicine, including herbal supplements. This 

research covers a wide range 

of studies—from laboratorybased research studying how 

herbs might affect the body, to 

large clinical trials testing their 

use in people, such as studying 

ginkgo’s effects on memory 

in older adults, or whether 

St. John’s wort may help 

people with minor depression. Exploring how and why 

botanicals act in the body is an 

important step in evaluating 

their safety and effectiveness. 

herbal

supplements:

a word about safety

Although herbs have been 

used for thousands of years 

as natural medicines, natural 

does not always mean safe. 

Herbs can act in your body 

in ways similar to prescription 

drugs, and herbs may have 

side effects. They may also 

affect how your body responds 

to prescription drugs or overthe-counter medicines you 

take—possibly decreasing or 

increasing their effects. 

How are herbal supplements regulated?

The U.S. Food and Drug Administration (FDA) regulates 

herbal and other dietary supplements differently from 

conventional medicines. The standards of safety and 

effectiveness that prescription and over-the-counter 

medicines have to meet before they are marketed 

do not apply to supplements. The standards for 

supplements are found in the Dietary Supplement 

Health and Education Act (DSHEA), a Federal law that 

defines dietary supplements and sets product-labeling standards and health claim limits. To learn more 

about DSHEA, visit the FDA Web site at www.fda.gov/

RegulatoryInformation/Legislation/.

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Use Caution

If you are considering or 

using an herbal supplement, 

think about these points:

s  Some herbal supplements 

are known to interact with 

medicines (both prescription 

and over-the-counter). For 

example, St. John’s wort 

can interact with birth 

control pills.

s  Research has shown that 

what’s listed on the label 

of an herbal supplement 

may not be what’s in the 

bottle. You may be getting 

less—or more—of an 

ingredient than the label 

indicates, even if it uses 

the word “standardized” 

or “certified.” Many factors, 

including manufacturing 

and storage methods, can 

affect the contents of an 

herbal product. 

s  Some herbal supplements 

have been found to be 

contaminated with metals, 

unlabeled prescription 

drugs, microorganisms, or 

other substances.

s  If you use herbal supple-

ments, it is best to do so 

under the guidance of a 

medical professional who 

has been properly trained 

in herbal medicine. This 

is especially important 

for herbs that are part of 

a whole medical system, 

such as traditional Chinese 

medicine or Ayurvedic 

medicine.

s  Women who are pregnant 

or nursing should be 

especially cautious about 

using herbal supplements. 

This caution also applies 

to giving children herbal 

supplements.

Talk to Your Health 

Care Providers

Be an informed consumer. 

Tell all of your health care 

providers about any herbs or 

supplements you are using 

or considering. 

Your health care providers need 

a full picture of everything 

you do to manage your health, 

including all complementary 

and alternative medicine 

practices. This will help ensure 

coordinated and safe care. It 

is especially important if you 

are taking any prescription or 

over-the-counter medications 

that could interact with an 

herbal supplement. 

For tips about talking with 

your health care providers 

about CAM, see NCCAM’s 

Time to Talk campaign at 

nccam.nih.gov/timetotalk/.

This booklet is not designed to be a comprehensive 

source of information about these specific herbs. 

NCCAM has provided this material for your information. 

It is not intended to substitute for the medical exper-

tise and advice of your primary health care provider. 

We encourage you to discuss any decisions about 

treatment or care with your health care provider. The 

mention of any product, service, or therapy is not an 

endorsement by NCCAM.

Information about the safety and effectiveness of 

herbal supplements can change as new research 

results are reported. To check for recent updates, 

please visit the Herbs at a Glance series online at 

nccam.nih.gov/health/herbsataglance.htm.

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9

aloe vera

Aloe vera’s use can be traced back 6,000 years to early Egypt, where 

the plant was depicted on stone carvings. Known as the “plant of 

immortality,” aloe was presented as a burial gift to deceased pharaohs.

Common Names

aloe vera, aloe, burn plant, lily of the desert, elephant’s gall

Latin Names

Aloe vera, Aloe barbadensis

What It Is Used For

s Traditionally, aloe was used 

topically to heal wounds and 

for various skin conditions, and 

orally as a laxative.

s Today, in addition to traditional 

uses, people take aloe orally to 

treat a variety of conditions, 

including diabetes, asthma, 

epilepsy, and osteoarthritis. 

People use aloe topically for 

osteoarthritis, burns, sunburns, 

and psoriasis.

s Aloe vera gel can be found 

in hundreds of skin products, 

including lotions and sunblocks. 

s The FDA has approved aloe vera 

as a natural food flavoring.

How It Is Used

s Aloe leaves contain a clear gel 

that is often used as a topical 

ointment. 

s The green part of the leaf that 

surrounds the gel can be used 

to produce a juice or a dried 

substance (called latex) that 

is taken by mouth. 

What the Science Says

s Aloe latex contains strong 

laxative compounds. Products 

made with various components 

of aloe (aloin, aloe-emodin, 

and barbaloin) were at one 

time regulated by the FDA as 

oral over-the-counter (OTC) 

laxatives. In 2002, the FDA 

required that all OTC aloe 

laxative products be removed 

from the U.S. market or reformulated because the companies 

that manufactured them did 

not provide the necessary 

safety data. 

s Early studies show that topical 

aloe gel may help heal burns 

and abrasions. One study, 

however, showed that aloe 

gel inhibits healing of deep 

surgical wounds. Aloe gel 

has not been shown to prevent 

burns from radiation therapy.

s There is not enough scientific 

evidence to support aloe vera for 

any of its other uses.

Side Effects and Cautions

s Use of topical aloe vera is 

not associated with significant 

side effects.

s Abdominal cramps and diarrhea 

have been reported with oral 

use of aloe vera. 

s Diarrhea, caused by the 

laxative effect of oral aloe vera, 

can decrease the absorption of 

many drugs.

s People with diabetes who use 

glucose-lowering medication 

should be cautious if also taking 

aloe by mouth because preliminary studies suggest aloe may 

lower blood glucose levels.

s There have been a few case 

reports of acute hepatitis from 

aloe vera taken orally. However, 

the evidence is not definitive 

and the safety of aloe has not 

been systematically studied.

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10 11

asian ginseng

Asian ginseng is native to China and Korea and has been used in various 

systems of medicine for many centuries. Asian ginseng is one of several 

types of true ginseng (another is American ginseng, Panax quinquefolius). 

An herb called Siberian ginseng or eleuthero (Eleutherococcus senticosus) 

is not a true ginseng.

Common Names

Asian ginseng, ginseng, 

Chinese ginseng, Korean 

ginseng, Asiatic ginseng

Latin Name

Panax ginseng

What It Is Used For

Treatment claims for Asian 

ginseng are numerous and include 

the use of the herb to support 

overall health and boost the 

immune system. Traditional and 

modern uses of ginseng include:

s Improving the health of people 

recovering from illness

s Increasing a sense of well-being 

and stamina, and improving both 

mental and physical performance

s Treating erectile dysfunction, 

hepatitis C, and symptoms 

related to menopause

s Lowering blood glucose and 

controlling blood pressure.

How It Is Used

The root of Asian ginseng contains 

active chemical components called 

ginsenosides (or panaxosides) that 

are thought to be responsible for 

the herb’s medicinal properties. 

The root is dried and used to make 

tablets or capsules, extracts, and 

teas, as well as creams or other 

preparations for external use.

What the Science Says

s Some studies have shown that 

Asian ginseng may lower blood 

glucose. Other studies indicate 

possible beneficial effects on 

immune function.

s Although Asian ginseng has 

been widely studied for a variety 

of uses, research results to date 

do not conclusively support 

health claims associated with 

the herb. Only a few large, 

high-quality clinical trials have 

been conducted. Most evidence 

is preliminary—i.e., based on 

laboratory research or small 

clinical trials.

s NCCAM supports studies to 

better understand the use of 

Asian ginseng. Areas of recent 

NCCAM-funded research 

include the herb’s potential role 

in treating insulin resistance, 

cancer, and Alzheimer’s disease.

Side Effects and Cautions

s  Short-term use of ginseng at 

recommended doses appears to 

be safe for most people. Some 

sources suggest that prolonged 

use might cause side effects.

s  The most common side effects 

are headaches and sleep and 

gastrointestinal problems.

s  Asian ginseng can cause 

allergic reactions.

s  There have been reports of 

breast tenderness, menstrual 

irregularities, and high blood 

pressure associated with Asian 

ginseng products, but these 

products’ components were not 

analyzed, so effects may have 

been due to another herb or 

drug in the product.

s Asian ginseng may lower levels 

of blood sugar; this effect may 

be seen more in people with 

diabetes. Therefore, people 

with diabetes should use extra 

caution with Asian ginseng, 

especially if they are using 

medicines to lower blood sugar 

or taking other herbs, such as 

bitter melon and fenugreek, 

that are also thought to lower 

blood sugar.
 

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What It Is Used For

s Historically, astragalus has 

been used in traditional 

Chinese medicine, usually 

in combination with other 

herbs, to support and enhance 

the immune system. It is 

still widely used in China for 

chronic hepatitis and as an 

adjunctive therapy in cancer.

s It is also used to prevent and 

treat common colds and upper 

respiratory infections.

s Astragalus has also been used 

for heart disease.

Common Names

astragalus, bei qi, huang qi, 

ogi, hwanggi, milk vetch

Latin Names

Astragalus membranaceus, 

Astragalus mongholicus

How It Is Used

The root of the astragalus plant 

is typically used in soups, teas, 

extracts, or capsules. Astragalus 

is generally used with other 

herbs, such as ginseng, angelica, 

and licorice.

What the Science Says

s The evidence for using astragalus for any health condition 

is limited. High-quality clinical trials (studies in people) 

are generally lacking. There is 

some preliminary evidence to 

suggest that astragalus, either 

alone or in combination with 

other herbs, may have potential 

benefits for the immune system, 

heart, and liver, and as an 

adjunctive therapy for cancer.

s NCCAM-funded investigators 

are studying the effects of astragalus on the body, particularly 

on the immune system.

Side Effects and Cautions

s Astragalus is considered safe 

for most adults. Its possible 

side effects are not well known 

because astragalus is generally 

used in combination with 

other herbs. 

s Astragalus may interact with 

medications that suppress the 

immune system, such as the 

drug cyclophosphamide taken 

by cancer patients and similar 

drugs taken by organ transplant recipients. It may also 

affect blood sugar levels and 

blood pressure.

s People should be aware that 

some astragalus species, usually 

not found in dietary supplements 

used by humans, can be toxic. 

For example, several species 

that grow in the United States 

contain the neurotoxin swainsonine and have caused “locoweed” 

poisoning in animals. Other 

species contain potentially toxic 

levels of selenium.

astragalus

12

Native to China, astragalus has been used for centuries in traditional 

Chinese medicine. In the United States, the herb gained popularity in 

the 1980s. There are actually over 2,000 species of astragalus; however, 

the two related species Astragalus membranaceus and Astragalus 

mongholicus are the ones primarily used for health purposes.
14 15

 

 

 

 

bilberry

Bilberry is a relative of the blueberry, and its fruit is commonly used 

to make pies and jams. It has been used for nearly 1,000 years in 

traditional European medicine. Bilberry grows in North America, Europe, 

and northern Asia.

Common Names

bilberry, European blueberry, whortleberry, huckleberry

Latin Name

Vaccinium myrtillus

What It Is Used For

s Historically, bilberry fruit was 

used to treat diarrhea, scurvy, 

and other conditions.

s Today, the fruit is used to treat 

diarrhea, menstrual cramps, 

eye problems, varicose veins, 

venous insufficiency (a condition in which the veins do not 

efficiently return blood from 

the legs to the heart), and other 

circulatory problems.

s Bilberry leaf is used for entirely 

different conditions, including 

diabetes.

How It Is Used

The fruit of the bilberry plant can 

be eaten or made into extracts. 

Similarly, the leaves of the 

bilberry plant can be made into 

extracts or used to make teas.

What the Science Says

s Some claim that bilberry 

fruit improves night vision, 

but clinical studies have not 

shown this to be true.

s There is not enough scientific 

evidence to support the use 

of bilberry fruit or leaf for 

any health conditions.

Side Effects and Cautions

s Bilberry fruit is considered safe 

when consumed in amounts 

typically found in foods, or 

as an extract in recommended 

doses for brief periods of time. 

Long-term safety and side 

effects have not been extensively studied. 

s High doses or extended use 

of bilberry leaf or leaf extract 

are considered unsafe due to 

possible toxic side effects.
16 17

bitter orange

The bitter orange tree is native to eastern Africa and tropical Asia. Today, 

it is grown throughout the Mediterranean region and elsewhere, including 

California and Florida. Bitter orange oil is used in foods, cosmetics, and 

aromatherapy products. Bitter orange oil from the tree’s leaves is called 

petitgrain, and oil from the flowers is called neroli.

Common Names

bitter orange, Seville orange, 

sour orange, Zhi shi

Latin Name

Citrus aurantium

What It Is Used For

s Bitter orange has been used in 

traditional Chinese medicine 

and by indigenous people of the 

Amazon rainforest for nausea, 

indigestion, and constipation.

s Current uses of bitter orange are 

for heartburn, loss of appetite, 

nasal congestion, and weight 

loss. It is also applied to the skin 

for fungal infections such as 

ringworm and athlete’s foot.

How It Is Used

The dried fruit and peel (and 

sometimes flowers and leaves) are 

taken by mouth in extracts, tablets, 

and capsules. Bitter orange oil can 

be applied to the skin.

What the Science Says

s There is not enough scientific 

evidence to support the use of 

bitter orange for health purposes.

s Many herbal weight-loss 

products now use concentrated 

extracts of bitter orange peel 

in place of ephedra. However, 

bitter orange contains the 

chemical synephrine, which is 

similar to the main chemical 

in ephedra. The FDA banned 

ephedra because it raises 

blood pressure and is linked to 

heart attacks and strokes; it is 

unclear whether bitter orange 

has similar effects. There is 

currently little evidence that 

bitter orange is safer to use 

than ephedra.

Side Effects and Cautions

s Because bitter orange contains 

chemicals that may speed up 

the heart rate and raise blood 

pressure, it may not be safe to 

use as a dietary supplement. 

There have been reports of 

fainting, heart attack, and stroke 

in healthy people after taking 

bitter orange supplements alone 

or combined with caffeine. 

People should avoid taking 

bitter orange supplements if 

they have a heart condition or 

high blood pressure, or if they 

are taking medications (such as 

MAO inhibitors), caffeine, or 

other herbs/supplements that 

speed up the heart rate.

s Due to lack of safety evidence, 

pregnant women or nursing 

mothers should avoid products 

that contain bitter orange.

s Bitter orange oil used on the 

skin may increase the risk of 

sunburn, particularly in lightskinned people.
18 19

What It Is Used For

s Black cohosh has a history of 

use for rheumatism (arthritis 

and muscle pain) but has been 

used more recently to treat hot 

flashes, night sweats, vaginal 

dryness, and other symptoms 

that can occur during menopause.

s Black cohosh has also been used 

for menstrual irregularities and 

premenstrual syndrome, and to 

induce labor.

How It Is Used

The underground stems and roots 

of black cohosh are commonly used 

fresh or dried to make strong teas 

(infusions), capsules, solid extracts 

used in pills, or liquid extracts 

(tinctures).

What the Science Says

s Study results are mixed on 

whether black cohosh effectively relieves menopausal 

symptoms. An NCCAM-funded 

study found that black cohosh, 

whether used alone or with 

other botanicals, failed to relieve 

hot flashes and night sweats in 

postmenopausal women or those 

approaching menopause.

s Most studies to date have 

been less than 6 months long, 

so the safety of long-term use 

is uncertain. 

Common Names

black cohosh, black snakeroot, 

macrotys, bugbane, bugwort, 

rattleroot, rattleweed

Latin Names

Actaea racemosa, Cimicifuga 

racemosa

s NCCAM is funding studies 

to further understand the 

potential effects of black 

cohosh on hot flashes and other 

menopausal symptoms.

s There are not enough reliable 

data to determine whether black 

cohosh is effective for rheumatism or other uses. 

Side Effects and Cautions

s United States Pharmacopeia 

experts suggest women should 

discontinue use of black cohosh 

and consult a heath care practitioner if they have a liver disorder 

or develop symptoms of liver 

trouble, such as abdominal pain, 

dark urine, or jaundice. There have 

been several case reports of hepatitis (inflammation of the liver), as 

well as liver failure, in women who 

were taking black cohosh. It is not 

known if black cohosh was responsible for these problems. Although 

these cases are very rare and the 

evidence is not definitive, scientists 

are concerned about the possible 

effects of black cohosh on the liver.

s Some people taking black cohosh 

have experienced side effects such 

as stomach discomfort, headache, 

or rash. In general, clinical trials 

of black cohosh for menopausal 

symptoms have not found serious 

side effects.

s Although concerns have been 

raised about possible interactions 

between black cohosh and various 

medications, a 2008 review of 

studies to date concluded that the 

risk of such interactions appears 

to be small.

s It is not clear if black cohosh is 

safe for women who have had 

hormone-sensitive conditions such 

as breast cancer or for pregnant 

women or nursing mothers.

s Black cohosh should not be confused 

with blue cohosh (Caulophyllum 

thalictroides), which has different properties, treatment uses, 

and side effects than black cohosh. 

Black cohosh is sometimes used 

with blue cohosh to stimulate 

labor, but this therapy has caused 

adverse effects in newborns, which 

appear to be due to blue cohosh.

black cohosh

Black cohosh, a member of the buttercup family, is a plant native to 

North America. It was used in Native American medicine and was a 

home remedy in 19th-century America.
20 21

cat’s claw

Cat’s claw grows wild in many countries of Central and South America, 

especially in the Amazon rainforest. The use of this woody vine dates 

back to the Inca civilization.

Common Names

cat’s claw, uña de gato

Latin Names

Uncaria tomentosa, 

Uncaria guianensis

What It Is Used For

s Cat’s claw has been used for 

centuries in South America to 

prevent and treat disease. 

s It has been used for a variety 

of health conditions, including 

viral infections (such as herpes 

and HIV), Alzheimer’s disease, 

cancer, and arthritis. 

s Cat’s claw has been used to 

support the immune system 

and promote kidney health, as 

well as to prevent and abort 

pregnancy.

How It Is Used

The inner bark of cat’s claw is used 

to make liquid extracts, capsules, 

and teas. Preparations of cat’s claw 

can also be applied to the skin.

What the Science Says

s There is not enough scientific 

evidence to determine whether 

cat’s claw works for any health 

condition. 

s Small studies in humans have 

shown a possible benefit of 

cat’s claw in osteoarthritis and 

rheumatoid arthritis, but no 

large trials have been done. In 

laboratory studies, cat’s claw 

stimulates part of the immune 

system, but it has not been 

proven to reduce inflammation 

or boost the immune system 

in humans.

s The National Institute on Aging 

funded a study that looked at 

how cat’s claw may affect the 

brain. Findings may point to 

new avenues for research in 

Alzheimer’s disease treatment.

Side Effects and Cautions

s Few side effects have been 

reported for cat’s claw when it is 

taken at recommended dosages. 

Though rare, side effects may 

include headaches, dizziness, 

and vomiting.

s Women who are pregnant or 

trying to become pregnant should 

avoid using cat’s claw because of 

its past use for preventing and 

aborting pregnancy.

s Because cat’s claw may stimulate 

the immune system, it is unclear 

whether the herb is safe for 

people with conditions affecting 

the immune system.

s Cat’s claw may interfere with 

controlling blood pressure 

during or after surgery.
22 23

What It Is Used For

s Chamomile has been widely 

used in children and adults for 

thousands of years for a variety 

of health conditions.

s The herb is often used for sleeplessness; anxiety; and gastrointestinal conditions such as upset 

stomach, gas, and diarrhea. 

s It is used topically for skin 

conditions and for mouth ulcers 

resulting from cancer treatment.

Common Names

chamomile, German chamomile

Latin Names

Matricaria recutita, 

Chamomilla recutita

How It Is Used

The flowering tops of the chamomile plant are used to make teas, 

liquid extracts, capsules, or tablets. 

The herb can also be applied to the 

skin as a cream or an ointment, or 

used as a mouth rinse.

What the Science Says

s Chamomile has not been well 

studied in people so there is little 

evidence to support its use for 

any condition.

s Some early studies point to 

chamomile’s possible benefits 

for certain skin conditions and 

for mouth ulcers caused by 

chemotherapy or radiation.

s In combination with other herbs, 

chamomile may be of some 

benefit for upset stomach, for 

diarrhea in children, and for 

infants with colic.

s NCCAM-funded research on 

chamomile includes studies of 

the herb for generalized anxiety 

disorder and for abdominal 

pain caused by children’s 

bowel disorders. 

Side Effects and Cautions

s There are reports of allergic 

reactions in people who have 

eaten or come into contact with 

chamomile products. Reactions 

can include skin rashes, throat 

swelling, shortness of breath, and 

anaphylaxis (a life-threatening 

allergic reaction).

s People are more likely to 

experience allergic reactions to 

chamomile if they are allergic 

to related plants in the daisy 

family, which includes ragweed, 

chrysanthemums, marigolds, 

and daisies.

chamomile

Two types of chamomile are used for health conditions: German chamomile and Roman chamomile. While the two kinds are thought to have 

similar effects on the body, the German variety is more commonly used 

in the United States and is the focus of this summary.
24 25

chasteberry

Chasteberry is the fruit of the chaste tree, a small shrub-like tree native 

to Central Asia and the Mediterranean region. The name is thought to 

come from a belief that the plant promoted chastity—it is reported that 

monks in the Middle Ages used chasteberry to decrease sexual desire.

Common Names

chasteberry, chaste-tree berry, vitex, monk’s pepper

Latin Name

Vitex agnus-castus

What It Is Used For

s Chasteberry has been used 

for thousands of years, mostly 

by women to ease menstrual 

problems and to stimulate the 

production of breast milk.

s Chasteberry is still used for 

menstrual problems, such as 

premenstrual syndrome, as 

well as for symptoms of 

menopause, some types of 

infertility, and acne.

How It Is Used

The dried ripe chasteberry is used 

to prepare liquid extracts or solid 

extracts that are put into capsules 

and tablets. 

What the Science Says

s A few studies of chasteberry 

for premenstrual syndrome 

have found a benefit. However, 

most of these studies were not 

well designed, so firm conclusions about chasteberry for 

premenstrual syndrome cannot 

be drawn. 

s Small studies suggest that 

chasteberry may help with 

breast pain and some types 

of infertility, but there is not 

enough reliable scientific 

evidence to determine whether 

chasteberry has any effect on 

these conditions.

s NCCAM has funded studies 

on chasteberry. Projects have 

explored how chasteberry works 

in the body and how it might 

affect symptoms of premenstrual 

syndrome.

Side Effects and Cautions

s Chasteberry has not been 

associated with serious side 

effects. However, it can cause 

gastrointestinal problems, acnelike rashes, and dizziness.

s Chasteberry may affect certain 

hormone levels. Women who 

are pregnant or taking birth 

control pills or who have a 

hormone-sensitive condition 

(such as breast cancer) should 

not use chasteberry.

s Because chasteberry may 

affect the dopamine system 

in the brain, people taking 

dopamine-related medications, 

such as certain antipsychotic 

drugs and Parkinson’s disease 

medications, should avoid using 

chasteberry.
26 27

cranberry

Cranberries are the fruit of a native plant of North America. These red 

berries are used in foods and in herbal products.

Common Names

cranberry, American cranberry, 

bog cranberry

Latin Name

Vaccinium macrocarpon

What It Is Used For

s Historically, cranberry fruits 

and leaves were used for a 

variety of problems, such as 

wounds, urinary disorders, 

diarrhea, diabetes, stomach 

ailments, and liver problems.

s Recently, cranberry products 

have been used in the hope of 

preventing or treating urinary 

tract infections or Helicobacter 

pylori (H. pylori) infections that 

can lead to stomach ulcers, or to 

prevent dental plaque. Cranberry 

has also been reported to have 

antioxidant and anticancer 

activity.

How It Is Used

The berries are used to produce 

beverages and many other food 

products, as well as dietary 

supplements in the form of 

extracts, capsules, or tablets.

What the Science Says

s There is some evidence that 

cranberry can help to prevent

urinary tract infections; 

however, the evidence is not 

definitive, and more research 

is needed. Cranberry has not 

been shown to be effective as a 

treatment for an existing urinary 

tract infection. 

s Research shows that components found in cranberry may 

prevent bacteria, such as E. coli,

from clinging to the cells along 

the walls of the urinary tract 

and causing infection. There is 

also preliminary evidence that 

cranberry may reduce the ability 

of H. pylori bacteria to live in 

the stomach and cause ulcers.

s Findings from a few laboratory 

studies suggest that cranberry 

may have antioxidant properties 

and may also be able to reduce 

dental plaque (a cause of 

gum disease).

s NCCAM is funding studies of 

cranberry, primarily to better 

understand its effects on urinary 

tract infection. The Office of 

Dietary Supplements and other 

NIH agencies are also supporting 

cranberry research; for example, 

the National Institute on Aging 

is funding a laboratory study of 

potential anti-aging effects.

Side Effects and Cautions

s Drinking cranberry juice 

products appears to be safe, 

although excessive amounts 

could cause gastrointestinal 

upset or diarrhea.

s People who think they have a 

urinary tract infection should 

see a health care provider for 

proper diagnosis and treatment. 

Cranberry products should not 

be used to treat infection.

s There are some indications 

that cranberry should be used 

cautiously by people who take 

blood-thinning drugs (such as 

warfarin), medications that 

affect the liver, or aspirin.
28 29

dandelion

Dandelion greens are edible and are a rich source of vitamin A. 

Dandelion has been used in many traditional medical systems, 

including Native American and traditional Arabic medicine.

Common Names

dandelion, lion’s tooth, blowball

Latin Name

Taraxacum officinale

What It Is Used For

s Historically, dandelion was 

most commonly used to treat 

liver diseases, kidney diseases, 

and spleen problems. Less 

commonly, dandelion was used 

to treat digestive problems and 

skin conditions.

s Today, dandelion is used by 

some as a liver or kidney 

“tonic,” as a diuretic, and for 

minor digestive problems.

How It Is Used

The leaves and roots of the dandelion, or the whole plant, are used 

fresh or dried in teas, capsules, or 

extracts. Dandelion leaves are used 

in salads or as a cooked green, and 

the flowers are used to make wine.

What the Science Says

There is no compelling scientific 

evidence for using dandelion 

as a treatment for any medical 

condition.

Side Effects and Cautions

s Dandelion use is generally 

considered safe. However, there 

have been rare reports of upset 

stomach and diarrhea, and some 

people are allergic to the plant.

s People with an inflamed or 

infected gallbladder, or blocked 

bile ducts, should avoid using 

dandelion.
30 31

echinacea

There are nine known species of echinacea, all of which are native 

to the United States and southern Canada. The most commonly used, 

Echinacea purpurea, is believed to be the most potent. 

Common Names

echinacea, purple coneflower, coneflower, American coneflower

Latin Names

Echinacea purpurea, Echinacea angustifolia, Echinacea pallida

What It Is Used For

s Echinacea has traditionally been 

used to treat or prevent colds, flu, 

and other infections.

s Echinacea is believed to stimulate the immune system to help 

fight infections.

s Less commonly, echinacea has 

been used for wounds and skin 

problems, such as acne or boils.

How It Is Used

The aboveground parts of the 

plant and roots of echinacea are 

used fresh or dried to make teas, 

squeezed (expressed) juice, extracts, 

or preparations for external use.

What the Science Says

s Study results are mixed on 

whether echinacea can prevent

or effectively treat upper respiratory tract infections such as the 

common cold. For example, two 

NCCAM-funded studies did not 

find a benefit from echinacea, 

either as Echinacea purpurea

fresh-pressed juice for treating colds in children, or as an 

unrefined mixture of Echinacea 

angustifolia root and Echinacea 

purpurea root and herb in adults. 

However, other studies have 

shown that echinacea may be 

beneficial in treating upper 

respiratory infections.

s NCCAM is continuing to 

support the study of echinacea for the treatment of upper 

respiratory infections. NCCAM 

is also studying echinacea for 

its potential effects on the 

immune system.

Side Effects and Cautions

s When taken by mouth, echinacea usually does not cause side 

effects. However, some people 

experience allergic reactions, 

including rashes, increased 

asthma, and anaphylaxis (a lifethreatening allergic reaction). 

In clinical trials, gastrointestinal 

side effects were most common.

s People are more likely to 

experience allergic reactions to 

echinacea if they are allergic 

to related plants in the daisy 

family, which includes ragweed, 

chrysanthemums, marigolds, and 

daisies. Also, people with asthma 

or atopy (a genetic tendency 

toward allergic reactions) may 

be more likely to have an allergic 

reaction when taking echinacea.
32 33

What It Is Used For

s Ephedra has been used for 

more than 5,000 years in China 

and India to treat conditions such 

as colds, fever, flu, headaches, 

asthma, wheezing, and nasal 

congestion.

s It has also been an ingredient 

in many dietary supplements 

used for weight loss, increased 

energy, and enhanced athletic 

performance. 

How It Is Used

The dried stems and leaves of the 

plant are used to create capsules, 

tablets, extracts, tinctures, and teas.

What the Science Says

s An NCCAM-funded study that 

analyzed phone calls to poison 

control centers found a higher 

rate of side effects from ephedra, 

compared with other herbal 

products.

s Other studies and systematic 

reviews have found an increased 

risk of heart, psychiatric, and 

gastrointestinal problems, as 

well as high blood pressure and 

stroke, with ephedra use. 

s According to the FDA, there 

is little evidence of ephedra’s 

effectiveness, except for shortterm weight loss. However, the 

increased risk of heart problems 

and stroke outweighs any benefits.

Common Names

ephedra, Chinese ephedra, 

ma huang 

Latin Name

Ephedra sinica

Side Effects and Cautions

s In 2004, the FDA banned the 

U.S. sale of dietary supplements 

containing ephedra. The FDA 

found that these supplements 

had an unreasonable risk of 

injury or illness—particularly 

cardiovascular complications—

and a risk of death. The ban does 

not apply to traditional Chinese 

herbal remedies or to products 

like herbal teas regulated as 

conventional foods.*

s Between 1995 and 1997, 

the FDA received more than 

900 reports of possible ephedra 

toxicity. Serious adverse events 

such as stroke, heart attack, 

and sudden death were 

reported in 37 cases.

s Using ephedra may worsen 

many health conditions such 

as cardiovascular disease, kidney 

disease, and diabetes.

s Ephedra may cause seizures 

in otherwise healthy people 

as well as in people with 

seizure disorders.

s Taking ephedra can also result 

in anxiety, difficulty urinating, 

dry mouth, headache, heart 

damage, high blood pressure, 

irregular heart rhythms, irritation of the stomach, kidney 

stones, nausea, psychosis, 

restlessness, sleep problems, 

and tremors.

s Women who are pregnant or 

breastfeeding and children 

should avoid taking ephedra.

s Ephedra use may lead to serious 

health problems when used with 

other dietary supplements or 

medicines. 

s Combining ephedra with 

caffeine increases the risk of 

potentially serious side effects. 

*Products regulated as drugs that contain 

chemically synthesized ephedrine are not 

dietary supplements and are not covered 

by this rule. These include drugs used 

for the short-term treatment of asthma, 

bronchitis, and allergic reactions.

ephedra

Ephedra is an evergreen shrub-like plant native to Central Asia and 

Mongolia. The principal active ingredient, ephedrine, is a compound that 

can powerfully stimulate the nervous system and heart.
34 35

european elder

European elder is a tree native to Europe and parts of Asia and Africa, 

and it also grows in the United States. There are several different types 

of elder, such as American elder, but European elder is the type most 

often used as a supplement.

Common Names

European elder, black elder, 

elder, elderberry, elder flower, 

sambucus

Latin Name

Sambucus nigra

What It Is Used For

s Parts of the elder tree—such as 

the berries and flowers—have 

long been used for pain, swelling, infections, coughs, and skin 

conditions.

s Today, elderberry and elder 

flower are used for flu, colds, 

fevers, constipation, and sinus 

infections.

How It Is Used

The dried flowers (elder flower) 

and the cooked blue/black berries 

(elderberry) of the European elder 

tree are used in teas, liquid extracts, 

and capsules.

What the Science Says

s Although some small studies 

show that elderberry may relieve 

flu symptoms, the evidence is not 

strong enough to support this 

use of the berry.

s A few studies have suggested 

that a product containing elder 

flower and other herbs can help 

treat sinus infections when used 

with antibiotics, but further 

research is needed to confirm 

any benefit.

s No reliable information is 

available on the effectiveness of 

elderberry and elder flower for 

other uses.

Side Effects and Cautions

s Uncooked or unripe elderberries 

are toxic and can cause nausea, 

vomiting, or severe diarrhea. 

Only the blue/black berries of 

elder are edible.

s Because of elder flower’s possible 

diuretic effects, use caution if 

taking it with drugs that increase 

urination. 
36 37

What It Is Used For

s Mistletoe has been used for 

centuries in traditional medicine 

to treat seizures, headaches, and 

other conditions.

s Mistletoe is used mainly 

in Europe as a treatment 

for cancer.

How It Is Used

s The leafy shoots and berries 

of mistletoe are used to make 

extracts that can be taken by 

mouth.

s In Europe, mistletoe extracts 

are prescription drugs that are 

given by injection. In the United 

States, mistletoe by injection is 

available only in clinical trials.

What the Science Says

s Laboratory studies have found 

that mistletoe kills cancer cells 

and stimulates the immune 

system.

s The use of mistletoe to treat 

cancer has been studied in 

Europe in more than 30 clinical 

trials. Although improvements 

in survival or quality of life have 

been reported, almost all of the 

trials had major weaknesses in 

their design that raise doubts 

about the findings. For example, 

many of the studies had a small 

number of participants or did not 

have a control group.

Common Names

European mistletoe, mistletoe

Latin Name

Viscum album L.

s NCCAM cosponsored a clinical 

trial of mistletoe, given in 

combination with the drug 

gemcitabine, for cancer. The 

study looked at toxicity, safety, 

and immune system effects of 

mistletoe extract when combined 

with this chemotherapy drug.

Side Effects and Cautions

s Raw, unprocessed mistletoe is 

poisonous. Eating raw, unprocessed European mistletoe or 

American mistletoe can cause 

vomiting, seizures, a slowing of 

the heart rate, and even death. 

American mistletoe is unsafe for 

medicinal use.

s In countries where commercial 

mistletoe is available by injection, such as Germany, those 

extracts are considered to be 

generally safe when used according to product directions and 

under the supervision of a health 

care provider.

s Injected mistletoe extract may 

cause itching or redness in 

the area of the injection. Less 

commonly, side effects may 

include more extensive skin 

reactions, low-grade fevers, or 

flu-like symptoms. There have 

been very rare reports of more 

serious allergic reactions, such as 

difficulty breathing.

s Because mistletoe has not yet 

been proven to be a safe and 

effective cancer treatment, it 

should not be used outside of 

clinical trials.

European mistletoe is a semiparasitic plant that grows on several types of 

trees in temperate regions worldwide. Where the term “mistletoe” is used 

in this summary, it refers to European mistletoe. (European mistletoe is 

different from American mistletoe, which is used as a holiday decoration.)

european mistletoe
38 39

evening primrose oil

Evening primrose is a plant native to North America, but it grows in 

Europe and parts of the Southern Hemisphere as well. It has yellow 

flowers that bloom in the evening. Evening primrose oil contains 

gamma-linolenic acid (GLA), an essential fatty acid. Essential fatty acids 

are required by the body for growth and development, and must be 

obtained from the diet.

Common Names

evening primrose oil, EPO

Latin Name

Oenothera biennis

What It Is Used For

s Evening primrose oil has been 

used since the 1930s for eczema 

(a condition in which the skin 

becomes inflamed, itchy, or scaly 

because of allergies or other 

irritation).

s More recently it has been used 

for other conditions involving 

inflammation, such as rheumatoid arthritis.

s Evening primrose oil is used for 

conditions affecting women’s 

health, such as breast pain 

associated with the menstrual 

cycle, menopausal symptoms, 

and premenstrual syndrome. 

s Other conditions for which 

evening primrose oil is used 

include cancer and diabetes.

How It Is Used

Evening primrose oil is extracted 

from the seeds of the evening 

primrose. The oil is usually put 

into capsules for use.

What the Science Says

s Evening primrose oil may have 

modest benefits for eczema, 

and it may be useful for 

rheumatoid arthritis and breast 

pain. However, study results 

are mixed, and most studies 

have been small and not well 

designed.

s Evening primrose oil does not 

appear to affect menopausal 

symptoms. 

s Although some clinical trials 

have shown a benefit of evening 

primrose oil for premenstrual 

syndrome, the best-designed 

trials found no effect. 

s There is not enough evidence 

to support the use of evening 

primrose oil for other health 

conditions.

Side Effects and Cautions

s Evening primrose oil is well 

tolerated by most people. Mild 

side effects include gastrointestinal upset and headache.
40 41

fenugreek

The first recorded use of fenugreek is described on an ancient 

Egyptian papyrus dated to 1500 B.C. Fenugreek seed is commonly 

used in cooking.

Common Names

fenugreek, fenugreek seed

Latin Name

Trigonella foenum-graecum 

What It Is Used For

s Historically, fenugreek was used 

for a variety of health conditions, 

including menopausal symptoms 

and digestive problems. It was 

also used for inducing childbirth.

s Today, it is used for diabetes and 

loss of appetite, and to stimulate 

milk production in breastfeeding 

women. It is also applied to the 

skin to treat inflammation.

How It Is Used

The dried seeds are ground and 

taken by mouth or used to form a 

paste that is applied to the skin.

What the Science Says

s A few small studies have found 

that fenugreek may help lower 

blood sugar levels in people with 

diabetes. 

s There is not enough scientific 

evidence to support the use of 

fenugreek for any other health 

condition.

Side Effects and Cautions

s Possible side effects of fenugreek 

when taken by mouth include 

gas, bloating, and diarrhea. 

Fenugreek can cause irritation 

when applied to the skin.

s Given its historical use for 

inducing childbirth, women 

should use caution when taking 

fenugreek during pregnancy.
42 43

feverfew

Originally a plant native to the Balkan mountains of Eastern Europe, 

feverfew—a short bush with daisy-like flowers—now grows throughout 

Europe, North America, and South America.

Common Names

feverfew, bachelor’s buttons, 

featherfew

Latin Names

Tanacetum parthenium, 

Chrysanthemum parthenium

What It Is Used For

s Feverfew has been used for 

centuries for fevers, headaches, 

stomach aches, toothaches, insect 

bites, infertility, and problems 

with menstruation and with 

labor during childbirth.

s Recently, feverfew has been 

used for migraine headaches 

and rheumatoid arthritis. 

s Feverfew has also been used 

for psoriasis, allergies, asthma, 

tinnitus (ringing or roaring 

sounds in the ears), dizziness, 

nausea, and vomiting. 

How It Is Used

s The dried leaves—and 

sometimes flowers and stems—

of feverfew are used to make 

supplements, including capsules, 

tablets, and liquid extracts.

s The leaves are sometimes 

eaten fresh. 

What the Science Says

s Some research suggests that 

feverfew may be helpful in 

preventing migraine headaches; 

however, results have been mixed 

and more evidence is needed 

from well-designed studies. 

s One study found that feverfew did not reduce rheumatoid arthritis symptoms in 

women whose symptoms did 

not respond to conventional 

medicines. It has been suggested 

that feverfew could help those 

with milder symptoms.

s There is not enough evidence 

available to assess whether 

feverfew is beneficial for 

other uses.

s NCCAM-funded researchers 

have studied ways to standardize feverfew; that is, to prepare 

it in a consistent manner. 

Standardized preparations can 

be used in future studies of 

feverfew for migraines.

Side Effects and Cautions

s No serious side effects have 

been reported for feverfew. Side 

effects can include canker sores, 

swelling and irritation of the lips 

and tongue, and loss of taste.

s Less common side effects 

can include nausea, digestive 

problems, and bloating. 

s People who take feverfew for a 

long time and then stop taking 

it may have headaches, nervousness, difficulty sleeping, stiff 

muscles, and joint pain.

s Women who are pregnant should 

not use feverfew because it may 

cause the uterus to contract, 

increasing the risk of miscarriage 

or premature delivery.

s People can have allergic reactions 

to feverfew. Those who are 

allergic to other members of the 

daisy family (which includes 

ragweed and chrysanthemums) 

are more likely to be allergic to 

feverfew.
44 45

What It Is Used For

s Flaxseed is most commonly 

used as a laxative.

s Flaxseed is also used for hot 

flashes and breast pain.

s Flaxseed oil is used for different 

conditions than flaxseed, 

including arthritis.

s Both flaxseed and flaxseed oil 

have been used for high 

cholesterol levels and in an 

effort to prevent cancer.

How It Is Used

Whole or crushed flaxseed can 

be mixed with water or juice and 

taken by mouth. Flaxseed is also 

available in powder form. Flaxseed 

oil is available in liquid and capsule 

form. Flaxseed contains lignans 

(phytoestrogens, or plant estrogens), while flaxseed oil preparations lack lignans.

What the Science Says

s Flaxseed contains soluble fiber, 

like that found in oat bran, and 

may have a laxative effect.

Common Names

flaxseed, linseed

Latin Name

Linum usitatissimum

s Studies of flaxseed preparations 

to lower cholesterol levels report 

mixed results. A 2009 review of 

the clinical research found that 

cholesterol-lowering effects were 

more apparent in postmenopausal women and in people 

with high initial cholesterol 

concentrations.

s Some studies suggest that 

alpha-linolenic acid (a substance 

found in flaxseed and flaxseed 

oil) may benefit people with 

heart disease. But not enough 

reliable data are available to 

determine whether flaxseed is 

effective for heart conditions.

s Study results are mixed on 

whether flaxseed decreases 

hot flashes.

s Although some population 

studies suggest that flaxseed 

might reduce the risk of certain 

cancers, there is not enough 

research to support a recommendation for this use.

s NCCAM is funding studies 

on flaxseed. Recent studies 

are looking at its potential 

role in preventing or treating 

atherosclerosis (hardening of 

the arteries), breast cancer, 

and ovarian cysts.

Side Effects and Cautions

s Flaxseed and flaxseed oil 

supplements seem to be well 

tolerated. Few side effects 

have been reported.

s Flaxseed, like any supplemental 

fiber source, should be taken 

with plenty of water; otherwise, 

it could worsen constipation 

or, in rare cases, even cause intestinal blockage. Both flaxseed and 

flaxseed oil can cause diarrhea.

s The fiber in flaxseed may lower 

the body’s ability to absorb 

medications that are taken by 

mouth. Flaxseed should not be 

taken at the same time as any 

conventional oral medications 

or other dietary supplements.

flaxseed and

flaxseed oil

Flaxseed is the seed of the flax plant, which is believed to have 

originated in Egypt. It grows throughout Canada and the northwestern 

United States. Flaxseed oil comes from flaxseeds.
46 47

garlic

Garlic is the edible bulb from a plant in the lily family. It has been used as 

both a medicine and a spice for thousands of years.

Common Name

garlic

Latin Name

Allium sativum

What It Is Used For

s Garlic’s most common uses as a 

dietary supplement are for high 

cholesterol, heart disease, and 

high blood pressure.

s Garlic is also used to prevent 

certain types of cancer, including 

stomach and colon cancers.

How It Is Used

Garlic cloves can be eaten raw 

or cooked. They may also be dried 

or powdered and used in tablets 

and capsules. Raw garlic cloves 

can be used to make oils and 

liquid extracts.

What the Science Says

s Some evidence indicates that 

taking garlic can slightly lower 

blood cholesterol levels; studies 

have shown positive effects 

for short-term (1 to 3 months) 

use. However, an NCCAMfunded study on the safety and 

effectiveness of three garlic 

preparations (fresh garlic, dried 

powdered garlic tablets, and 

aged garlic extract tablets) for 

lowering blood cholesterol levels 

found no effect.

s Preliminary research suggests 

that taking garlic may slow the 

development of atherosclerosis 

(hardening of the arteries), a 

condition that can lead to heart 

disease or stroke.

s Evidence suggests that taking 

garlic may slightly lower blood 

pressure, particularly in people 

with high blood pressure.

s Some studies suggest consuming garlic as a regular part of 

the diet may lower the risk of 

certain cancers. However, no 

clinical trials have examined this. 

A clinical trial on the long-term 

use of garlic supplements to 

prevent stomach cancer found 

no effect.

s Recent NCCAM-funded research 

includes studies on how garlic 

interacts with certain drugs; its 

effects on liver function and 

the dilation and constriction 

of blood vessels; and the 

bioavailability (how well a 

substance is absorbed by the 

body) of allicin, the main active 

compound of garlic.

Side Effects and Cautions

s Garlic appears to be safe for most 

adults.

s Side effects include breath and 

body odor, heartburn, upset 

stomach, and allergic reactions. 

These side effects are more 

common with raw garlic.

s Garlic can thin the blood (reduce 

the ability of blood to clot) in a 

manner similar to aspirin. This 

effect may be a problem during 

or after surgery. Use garlic with 

caution if you are planning to 

have surgery or dental work, or 

if you have a bleeding disorder.

s Garlic has been found to 

interfere with the effectiveness 

of saquinavir, a drug used to 

treat HIV infection. Its effect 

on other drugs has not been 

well studied.
48

effects 

49

What It Is Used For

s Ginger is used in Asian medicine 

to treat stomach aches, nausea, 

and diarrhea.

s Many digestive, antinausea, and 

cold and flu dietary supplements 

sold in the United States contain 

ginger extract as an ingredient.

s Ginger is used to alleviate 

postsurgery nausea as well 

as nausea caused by motion, 

chemotherapy, and pregnancy.

s Ginger has been used for 

rheumatoid arthritis, osteoarthritis, and joint and muscle pain.

How It Is Used

The underground stems of the 

ginger plant are used in cooking, 

baking, and for health purposes. 

Common forms of ginger include 

fresh or dried root, tablets, capsules, 

liquid extracts (tinctures), and teas.

What the Science Says

s Studies suggest that the shortterm use of ginger can safely 

relieve pregnancy-related nausea 

and vomiting.

s Studies are mixed on whether 

ginger is effective for nausea 

caused by motion, chemotherapy, 

or surgery.

Common Name

ginger

Latin Name

Zingiber officinale

s It is unclear whether ginger is 

effective in treating rheumatoid 

arthritis, osteoarthritis, or joint 

and muscle pain.

s NCCAM-funded investigators 

have looked at whether ginger 

interacts with drugs, such as those 

used to suppress the immune 

system, and ginger’s effects on 

reducing nausea and vomiting. 

Investigators are also studying:

The general safety and effectiveness of ginger’s use for health 

purposes, as well as its active 

components and on 

inflammation

The effects of ginger dietary 

supplements on joint inflammation, rheumatoid arthritis, and 

osteoporosis.

Side Effects and Cautions

s Few side effects are linked 

to ginger when it is taken in 

small doses.

s Side effects most often reported 

are gas, bloating, heartburn, and 

nausea. These effects are most 

often associated with powdered 

ginger.

ginger

Ginger is a tropical plant that has green-purple flowers and an aromatic 

underground stem (called a rhizome). It is commonly used for cooking 

and medicinal purposes.
50 51

ginkgo

The ginkgo tree is one of the oldest types of trees in the world. Ginkgo 

seeds have been used in traditional Chinese medicine for thousands of 

years, and cooked seeds are occasionally eaten.

Common Names

ginkgo, Ginkgo biloba, fossil tree, maidenhair tree, Japanese silver apricot, 

baiguo, bai guo ye, kew tree, yinhsing (yin-hsing)

Latin Name

Ginkgo biloba

What It Is Used For

s Ginkgo leaf extract has been 

used to treat a variety of 

ailments and conditions, 

including asthma, bronchitis, 

fatigue, and tinnitus (ringing 

or roaring sounds in the ears).

s Today, people use ginkgo leaf 

extracts hoping to improve 

memory; to treat or help prevent 

Alzheimer’s disease and other 

types of dementia; to decrease 

intermittent claudication (leg pain 

caused by narrowing arteries); 

and to treat sexual dysfunction, 

multiple sclerosis, tinnitus, and 

other health conditions.

How It Is Used

Extracts are usually taken from 

the ginkgo leaf and are used to 

make tablets, capsules, or teas. 

Occasionally, ginkgo extracts 

are used in skin products.

What the Science Says

s Numerous studies of ginkgo 

have been done for a variety 

of conditions. Among the most 

widely researched are dementia, 

memory impairment, intermittent claudication, and tinnitus.

s An NCCAM-funded study of the 

well-characterized ginkgo product 

EGb-761 found it ineffective in 

lowering the overall incidence 

of dementia and Alzheimer’s 

disease in the elderly. Further 

analysis of the same data also 

found ginkgo to be ineffective in 

slowing cognitive decline, lowering blood pressure, or reducing 

the incidence of hypertension. In 

this clinical trial, known as the 

Ginkgo Evaluation of Memory 

study, researchers recruited more 

than 3,000 volunteers age 75 and 

over who took 240 mg of ginkgo 

daily. Participants were followed 

for an average of approximately 

6 years.

s Some smaller studies of ginkgo 

for memory enhancement have 

had promising results, but a 

trial sponsored by the National 

Institute on Aging of more than 

200 healthy adults over age 60 

found that ginkgo taken for 6 

weeks did not improve memory.

s Overall, the evidence on ginkgo 

for symptoms of intermittent 

claudication has not yet shown 

a significant benefit for this 

condition, although several 

small studies have found modest 

improvements. There is conflicting evidence on the efficacy of 

ginkgo for tinnitus.

s Other NCCAM-funded research 

includes studies on ginkgo for 

symptoms of multiple sclerosis, 

intermittent claudication, cognitive decline, sexual dysfunction 

due to antidepressants, insulin 

resistance, and short-term 

memory loss associated with 

electroconvulsive therapy 

for depression. 

Side Effects and Cautions

s Side effects of ginkgo may 

include headache, nausea, gastrointestinal upset, diarrhea, dizziness, or allergic skin reactions. 

More severe allergic reactions 

have occasionally been reported.

s There are some data to suggest 

that ginkgo can increase bleeding 

risk, so people who take anticoagulant drugs, have bleeding disorders, or have scheduled surgery 

or dental procedures should use 

caution and talk to a health care 

provider if using ginkgo.

s Fresh (raw) ginkgo seeds 

contain large amounts of a 

chemical called ginkgotoxin, 

which can cause serious adverse 

reactions—even seizures and 

death. Roasted seeds can also be 

dangerous. Products made from 

standardized ginkgo leaf extracts 

contain little ginkgotoxin and 

appear to be safe when used 

orally and appropriately.
52 53

goldenseal

Goldenseal is a plant that grows wild in parts of the United States 

but has become endangered by overharvesting. With natural supplies 

dwindling, goldenseal is now grown commercially across the United 

States, especially in the Blue Ridge Mountains.

Common Names

goldenseal, yellow root

Latin Name

Hydrastis canadensis

What It Is Used For

s Historically, Native Americans 

have used goldenseal for various 

health conditions such as skin 

diseases, ulcers, and gonorrhea.

s Now, goldenseal is used for 

colds and other respiratory tract 

infections, infectious diarrhea, 

eye infections, and vaginitis 

(inflammation or infection of the 

vagina). It is occasionally used to 

treat cancer. 

s It is also applied to wounds 

and canker sores, and is used 

as a mouthwash for sore gums, 

mouth, and throat.

How It Is Used 

s The underground stems or roots 

of goldenseal are dried and used 

to make teas, liquid extracts, and 

solid extracts that may be made 

into tablets and capsules.

s Goldenseal is often combined 

with echinacea in preparations 

that are intended to be used 

for colds.

What the Science Says

s Few studies have been published 

on goldenseal’s safety and 

effectiveness, and there is little 

scientific evidence to support 

using it for any health problem. 

s Clinical studies on a compound 

found in goldenseal, berberine, 

suggest that the compound may 

be beneficial for certain infections—such as those that cause 

some types of diarrhea, as well 

as some eye infections. However, 

goldenseal preparations contain 

only a small amount of berberine, 

so it is difficult to extend the 

evidence about the effectiveness 

of berberine to goldenseal.

s NCCAM is funding research 

on goldenseal, including studies 

of antibacterial mechanisms 

and potential cholesterollowering effects. NCCAM is 

also funding development of 

research-grade goldenseal, to 

facilitate clinical studies.

Side Effects and Cautions

s Goldenseal is considered safe 

for short-term use in adults at 

recommended dosages. Rare side 

effects may include nausea and 

vomiting.

s There is little information about 

the safety of high dosages or the 

long-term use of goldenseal.

s Goldenseal may cause changes 

in the way the body processes 

drugs, and could potentially alter 

the effects of many drugs.

s Other herbs containing berberine, 

including Chinese goldthread 

(Coptis trifolia) and Oregon 

grape (Mahonia aquifolium), 

are sometimes substituted for 

goldenseal. These herbs may have 

different effects, side effects, and 

drug interactions than goldenseal.

s Women who are pregnant or 

breastfeeding should avoid using 

goldenseal. Berberine, a chemical in goldenseal, can cause or 

worsen jaundice in newborns and 

could lead to a life-threatening 

problem called kernicterus.

s Goldenseal should not be given 

to infants and young children.
54 55

What It Is Used For

s Grape seed extract is used for 

conditions related to the heart 

and blood vessels, such as 

atherosclerosis (hardening of the 

arteries), high blood pressure, 

high cholesterol, and poor 

circulation. 

s Other reasons for the use of 

grape seed extract include 

complications related to diabetes, 

such as nerve and eye damage; 

vision problems, such as macular 

degeneration (which can cause 

blindness); and swelling after an 

injury or surgery. 

s Grape seed extract is also used 

for cancer prevention and wound 

healing.

How It Is Used

Grape seed extract is prepared from 

the seed of grapes. It is available in 

capsule and tablet forms.

What the Science Says

s Studies have found that some 

compounds of grape seed extract 

may be effective in relieving 

symptoms of chronic venous 

insufficiency (when veins have 

problems sending blood from 

the legs back to the heart) and 

reducing edema (swelling) after 

an injury or surgery.

Common Name

grape seed extract

Latin Name

Vitis vinifera

s Small randomized trials have 

found beneficial effects of grape 

seed extract for diabetic retinopathy (an eye problem caused by 

diabetes) and for vascular fragility (weakness in small blood 

vessels). Larger trials are needed 

to confirm these findings.

s Grape seed extract contains 

antioxidants, which help 

prevent cell damage caused by 

free radicals (highly reactive 

molecules that can damage cell 

function). Preliminary studies 

have shown some beneficial 

antioxidant effects; however, 

more research is needed.

s A study funded by the National 

Cancer Institute (NCI) found 

that grape seed extract did not 

reduce the hardening of breast 

tissue that can occur after radiation therapy for breast cancer.

s NCI is also funding studies to 

evaluate whether grape seed 

extract is effective in preventing 

breast cancer in postmenopausal 

women and prostate cancer. 

s NCCAM is studying whether 

the action of grape seed extract 

and its components may benefit 

the heart or help prevent cognitive decline, Alzheimer’s disease, 

and other brain disorders. 

Another study is investigating 

the effects of grape seed extract 

on colon cancer.

Side Effects and Cautions

s Grape seed extract is generally 

well tolerated when taken by 

mouth. It has been used safely for 

up to 8 weeks in clinical trials. 

s Side effects that have been 

reported include a dry, itchy 

scalp; dizziness; headache; 

high blood pressure; hives; 

indigestion; and nausea.

s The interactions between grape 

seed extract and medicines or 

other supplements have not 

been carefully studied.

grape seed extract

The grape seeds used to produce grape seed extract are generally 

obtained from wine manufacturers. The leaves and fruit of the grape have 

been used medicinally since ancient Greece.
56 57

green tea

All types of tea (green, black, and oolong) are produced from the 

Camellia sinensis plant using different methods. Fresh leaves 

from the Camellia sinensis plant are steamed to produce green tea.

Common Names

green tea, Chinese tea, Japanese tea

Latin Name

Camellia sinensis

What It Is Used For

s Green tea and green tea extracts, 

such as its component EGCG, 

have been used to prevent 

and treat a variety of cancers, 

including breast, stomach, and 

skin cancers.

s Green tea and green tea extracts 

have also been used for improving mental alertness, aiding in 

weight loss, lowering cholesterol 

levels, and protecting skin from 

sun damage.

How It Is Used

Green tea is usually brewed and 

drunk as a beverage. Green tea 

extracts can be taken in capsules 

and are sometimes used in skin 

products.

What the Science Says

s Laboratory studies suggest 

that green tea may help 

protect against or slow the 

growth of certain cancers, but 

studies in people have shown 

mixed results.

s Some evidence suggests that the 

use of green tea preparations 

improves mental alertness, most 

likely because of its caffeine 

content. There are not enough 

reliable data to determine 

whether green tea can aid in 

weight loss, lower blood cholesterol levels, or protect the skin 

from sun damage.

s NCCAM supports studies to 

learn more about the components 

in green tea and their effects on 

conditions such as cancer, diabetes, and heart disease.

Side Effects and Cautions

s Green tea is safe for most adults 

when used in moderate amounts.

s There have been some case 

reports of liver problems in 

people taking concentrated green 

tea extracts. This problem does 

not seem to be connected with 

green tea infusions or beverages. 

Although these cases are very 

rare and the evidence is not 

definitive, experts suggest that 

concentrated green tea extracts be 

taken with food and that people 

should discontinue use and 

consult a heath care practitioner 

if they have a liver disorder or 

develop symptoms of liver 

trouble, such as abdominal pain, 

dark urine, or jaundice.

s Green tea and green tea extracts 

contain caffeine. Caffeine can 

cause insomnia, anxiety, irritability, upset stomach, nausea, 

diarrhea, or frequent urination 

in some people. 

s Green tea contains small 

amounts of vitamin K, which can 

make anticoagulant drugs, such 

as warfarin, less effective.
58 59

hawthorn

Hawthorn is a spiny, flowering shrub or small tree of the rose family. 

The species of hawthorn discussed here are native to northern European 

regions and grow throughout the world.

Common Names

hawthorn, English hawthorn, 

harthorne, haw, hawthorne

Latin Names

Crataegus laevigata (also known 

as Crataegus oxyacantha),

Crataegus monogyna

What It Is Used For

s Hawthorn fruit has been used 

for heart disease since the first 

century. It has also been used for 

digestive and kidney problems. 

s More recently, hawthorn leaf 

and flower have been used for 

heart failure, a weakness of the 

heart muscle that prevents the 

heart from pumping enough 

blood to the rest of the body, 

which can lead to fatigue and 

limit physical activities. 

s Hawthorn is also used for other 

heart conditions, including 

symptoms of coronary artery 

disease (such as angina).

How It Is Used

The hawthorn leaf and flower 

are used to make liquid extracts, 

usually with water and alcohol. 

Dry extracts can be put into 

capsules and tablets.

What the Science Says

s There is scientific evidence that 

hawthorn leaf and flower may 

be safe and effective for milder 

forms of heart failure, but study 

results are conflicting.

s There is not enough scientific 

evidence to determine whether 

hawthorn works for other heart 

problems.

s NCCAM-supported research 

to date includes a study of the 

mechanism by which hawthorn 

may affect heart failure.

Side Effects and Cautions

s Hawthorn is considered safe 

for most adults when used for 

short periods of time. Side effects 

are rare and can include upset 

stomach, headache, and dizziness.

s Although drug interactions 

with hawthorn have not 

been thoroughly studied, 

there is evidence to suggest 

that hawthorn may interact 

with a number of different 

drugs, including certain heart 

medications.
60 61

hoodia

Hoodia is a flowering, cactus-like plant native to the Kalahari Desert 

in southern Africa. Its harvest is protected by conservation laws.

Common Names

hoodia, Kalahari cactus, Xhoba

Latin Name

Hoodia gordonii

What It Is Used For

s Kalahari Bushmen have traditionally eaten hoodia stems to 

reduce their hunger and thirst 

during long hunts.

s Today, hoodia is marketed as 

an appetite suppressant for 

weight loss.

How It Is Used

s Dried extracts of hoodia stems 

and roots are used to make 

capsules, powders, and chewable 

tablets. Hoodia can also be used 

in liquid extracts and teas.

s Hoodia products often contain 

other herbs or minerals, such 

as green tea or chromium 

picolinate.

What the Science Says

There is no reliable scientific 

evidence to support hoodia’s use. 

No studies of the herb in people 

have been published.

Side Effects and Cautions

s Hoodia’s safety is unknown. Its 

potential risks, side effects, and 

interactions with medicines and 

other supplements have not 

been studied.

s The quality of hoodia products 

varies widely. News reports 

suggest that some products 

sold as hoodia do not contain 

any hoodia.
62 63

What It Is Used For

s For centuries, horse chestnut 

seeds, leaves, bark, and flowers 

have been used for a variety of 

conditions and diseases.

s Horse chestnut seed extract 

has been used to treat chronic 

venous insufficiency (a condition in which the veins do not 

efficiently return blood from the 

legs to the heart). This condition 

is associated with varicose veins, 

pain, ankle swelling, feelings of 

heaviness, itching, and nighttime 

leg cramping.

s The seed extract has also been 

used for hemorrhoids.

Common Names

horse chestnut, buckeye, 

Spanish chestnut

Latin Name

Aesculus hippocastanum

How It Is Used

Horse chestnut seed extract 

standardized to contain 16 to 

20 percent aescin (escin), the active 

ingredient, is the most commonly 

used form. Topical preparations 

have also been used.

What the Science Says

s Studies have found that horse 

chestnut seed extract is beneficial in treating chronic venous 

insufficiency. There is also 

preliminary evidence that horse 

chestnut seed extract may be as 

effective as wearing compression stockings.

s There is not enough scientific 

evidence to support the use of 

horse chestnut seed, leaf, or bark 

for any other conditions.

Side Effects and Cautions

s Do not use raw or unprocessed 

horse chestnut seeds, leaves, 

bark, or flowers. They contain 

esculin, which is poisonous. 

s When properly processed, 

horse chestnut seed extract 

contains little or no esculin 

and is considered generally 

safe when used for short periods 

of time. However, the extract 

can cause some side effects, 

including itching, nausea, or 

gastrointestinal upset.

horse chestnut

Horse chestnut trees are native to the Balkan Peninsula (for example, 

Greece and Bulgaria), but grow throughout the Northern Hemisphere. 

Although horse chestnut is sometimes called buckeye, it should not be 

confused with the Ohio or California buckeye trees, which are related but 

not the same species.
64 65

kava

Kava is native to the islands of the South Pacific and is a member 

of the pepper family. Kava has been used as a ceremonial beverage 

in the South Pacific for centuries.

Common Names

kava, kava kava, awa, kava pepper

Latin Name

Piper methysticum

What It Is Used For s Kava has been used to help 

people fall asleep and fight 

fatigue, as well as to treat asthma 

and urinary tract infections.

s Topically, kava has been used as a 

numbing agent.

s Today, kava is used primarily for anxiety, insomnia, and 

menopausal symptoms.

How It Is Used

The root and rhizome (under-

ground stem) of kava are used 

to prepare beverages, extracts, 

capsules, tablets, and topical 

solutions.

What the Science Says s Although scientific studies 

provide some evidence that 

kava may be beneficial for the 

management of anxiety, the 

FDA has issued a warning that 

using kava supplements has been 

linked to a risk of severe liver 

damage.

s Kava is not a proven therapy 

for other uses.

s NCCAM-funded studies on kava 

were suspended after the FDA 

issued its warning.

Side Effects and Cautions s Kava has been reported to cause 

liver damage, including hepati-

tis and liver failure (which can 

cause death).

s Kava has been associated with 

several cases of dystonia (abnormal muscle spasm or involuntary muscle movements). 

Kava may interact with several 

drugs, including drugs used for 

Parkinson’s disease.

s Long-term and/or heavy use 

of kava may result in scaly, 

yellowed skin.

s Avoid driving and operating 

heavy machinery while taking 

kava because the herb has been 

reported to cause drowsiness.
66 67

lavender

Lavender is native to the Mediterranean region. It was used in ancient 

Egypt as part of the process for mummifying bodies. Lavender’s use 

as a bath additive originated in Persia, Greece, and Rome. The herb’s 

name comes from the Latin lavare, which means “to wash.”

Common Names

lavender, English lavender, garden lavender

Latin Name

Lavandula angustifolia

What It Is Used For

s Historically, lavender was used 

as an antiseptic and for mental 

health purposes.

s Today, the herb is used for conditions such as anxiety, restlessness, insomnia, and depression.

s Lavender is also used for 

headache, upset stomach, and 

hair loss.

How It Is Used

s Lavender is most commonly 

used in aromatherapy, in which 

the scent of the essential oil from 

the flowers is inhaled. 

s The essential oil can also be 

diluted with another oil and 

applied to the skin.

s Dried lavender flowers can 

be used to make teas or liquid 

extracts that can be taken 

by mouth.

What the Science Says

s There is little scientific evidence 

of lavender’s effectiveness for 

most health uses. 

s Small studies on lavender for 

anxiety show mixed results.

s Some preliminary results 

indicate that lavender oil, 

combined with oils from 

other herbs, may help with 

hair loss from a condition 

called alopecia areata.

Side Effects and Cautions

s Topical use of diluted lavender oil 

or use of lavender as aromatherapy is generally considered safe 

for most adults. However, applying lavender oil to the skin can 

cause irritation. There have been 

reports that topical use can cause 

breast growth in young boys.

s Lavender oil may be poisonous 

if taken by mouth. 

s When lavender teas and extracts 

are taken by mouth, they may 

cause headache, changes in 

appetite, and constipation.

s Using lavender with sedative 

medications may increase 

drowsiness.
68 69

licorice root

Most licorice is grown in Greece, Turkey, and Asia. Licorice contains 

a compound called glycyrrhizin (or glycyrrhizic acid). Licorice has 

a long history of medicinal use in both Eastern and Western systems 

of medicine.

Common Names

licorice root, licorice, liquorice, 

sweet root, gan zao (Chinese 

licorice)

Latin Names

Glycyrrhiza glabra, Glycyrrhiza 

uralensis (Chinese licorice)

What It Is Used For

Licorice root has been used as a 

dietary supplement for stomach 

ulcers, bronchitis, and sore throat, 

as well as infections caused by 

viruses, such as hepatitis.

How It Is Used 

s Peeled licorice root is available in 

dried and powdered forms. 

s Licorice root is available as 

capsules, tablets, and liquid 

extracts.

s Licorice can be found with 

glycyrrhizin removed; the 

product is called DGL (for 

“deglycyrrhizinated licorice”).

What the Science Says

s An injectable form of licorice 

extract—not available in the 

United States—has been shown 

to have beneficial effects against 

hepatitis C in clinical trials. 

There are no reliable data on oral 

forms of licorice for hepatitis C. 

More research is needed before 

reaching any conclusions.

s There are not enough reliable 

data to determine whether licorice 

is effective for any condition.

Side Effects and Cautions

s In large amounts, licorice 

containing glycyrrhizin can 

cause high blood pressure, salt 

and water retention, and low 

potassium levels, which could 

lead to heart problems. DGL 

products are thought to cause 

fewer side effects.

s The safety of using licorice as 

a supplement for more than 

4 to 6 weeks has not been 

thoroughly studied.

s Taking licorice together with 

diuretics (water pills), corticosteroids, or other medicines that 

reduce the body’s potassium 

levels could cause dangerously 

low potassium levels.

s People with heart disease or 

high blood pressure should be 

cautious about using licorice.

s When taken in large amounts, 

licorice can affect the body’s 

levels of a hormone called 

cortisol and related steroid 

drugs, such as prednisone.

s Pregnant women should avoid 

using licorice as a supplement 

or consuming large amounts of 

licorice as food, as some research 

suggests it could increase the 

risk of preterm labor. 
70 71

milk thistle

Milk thistle is a flowering herb that is native to the Mediterranean region. 

It has been used for thousands of years as a remedy for a variety of 

ailments, especially liver problems.

Common Names

milk thistle, Mary thistle, holy thistle. Milk thistle is sometimes called 

silymarin, which is actually a mixture of the herb’s active components, 

including silybinin (also called silibinin or silybin).

Latin Name

Silybum marianum

What It Is Used For

Milk thistle is believed to have 

protective effects on the liver and 

improve its function. It is typically 

used to treat liver cirrhosis, chronic 

hepatitis (liver inflammation), and 

gallbladder disorders. Treatment 

claims also include:

s Lowering cholesterol levels 

s Reducing insulin resistance in 

people with type 2 diabetes who 

also have cirrhosis

s Reducing the growth of cancer 

cells in breast, cervical, and 

prostate cancers.

How It Is Used

Silymarin, which can be extracted 

from the seeds (fruit) of the milk 

thistle plant, is believed to be 

the biologically active part of 

the herb. The seeds are used 

to prepare capsules, extracts, 

powders, and tinctures.

What the Science Says

s Laboratory studies suggest that 

milk thistle may benefit the liver 

by protecting and promoting the 

growth of liver cells, fighting 

oxidation (a chemical process that 

can damage cells), and inhibiting inflammation. Results from 

clinical trials of milk thistle for 

liver diseases have been mixed, 

and most studies have not been 

rigorously designed. Reviews 

of the research have concluded 

that the efficacy of milk thistle 

against liver disease has not 

been established, and additional, 

high-quality trials are needed.

s The Hepatitis C Antiviral 

Long-Term Treatment Against 

Cirrhosis (HALT) study, 

sponsored by NIH, found that 

silymarin use by hepatitis C 

patients was associated with 

fewer and milder symptoms 

of liver disease and somewhat 

better quality of life, but there 

was no change in virus activity 

or liver inflammation.

s NCCAM-funded research 

includes a number of studies 

on milk thistle for liver disease, 

such as a phase II trial to better 

understand the use of milk thistle 

for chronic hepatitis C. A study 

cofunded by NCCAM and the 

National Institute of Diabetes 

and Digestive and Kidney 

Diseases is examining the effects 

of milk thistle on people with 

chronic hepatitis C who have not 

responded to conventional antiviral treatment, and people with 

nonalcoholic steatohepatitis (liver 

disease that occurs in people who 

drink little or no alcohol).

s The National Cancer Institute 

is studying the effectiveness 

of silymarin for patients with 

leukemia who experience chemotherapy-related liver damage. 

The National Institute of Nursing 

Research is investigating whether 

milk thistle is an effective treatment for hepatitis C in people 

with both hepatitis C and HIV.

Side Effects and Cautions

s In clinical trials, milk thistle 

appears to be well tolerated in 

recommended doses. Occasionally, people report various 

gastrointestinal side effects.

s Milk thistle can produce allergic 

reactions, which tend to be more 

common among people who are 

allergic to plants in the same family 

(for example, ragweed, chrysanthemum, marigold, and daisy).

s Milk thistle may lower blood 

sugar levels. People with diabetes or hypoglycemia, or people 

taking drugs or supplements that 

affect blood sugar levels, should 

use caution.
72 73

What It Is Used For

s Noni has a history of use as a 

topical preparation for joint pain 

and skin conditions.

s Today, people drink noni fruit 

juice as a general health tonic, 

as well as for cancer and chronic 

conditions such as cardiovascular 

disease and diabetes.

How It Is Used

s Traditionally, the leaves and fruit 

of noni have been used for health 

purposes.

Common Names

noni, morinda, Indian mulberry, 

hog apple, canary wood

Latin Name

Morinda citrifolia

s Today, the fruit is most 

commonly combined with other 

fruits (such as grape) to make 

juice. Preparations of the fruit 

and leaves are also available in 

capsules, tablets, and teas.

What the Science Says

s In laboratory research, noni has 

shown antioxidant, immunestimulating, and tumor-fighting 

properties. These results suggest 

that noni may warrant further 

study for conditions such as 

cancer and cardiovascular 

disease. However, noni has 

not been well studied in people 

for any health condition.

s NCCAM-funded research 

includes a study on noni for 

cancer to determine its safety and 

potential effects on tumors and 

symptoms, as well as a laboratory 

study of noni’s effects on prostate 

cancer cells. The National Cancer 

Institute is funding preliminary 

research on noni for breast cancer 

prevention and treatment.

Side Effects and Cautions

s Noni is high in potassium. 

People who are on potassiumrestricted diets because of 

kidney problems should 

avoid using noni.

s Several noni juice manufacturers 

have received warnings from 

the FDA about making unsubstantiated health claims.

s Although there have been few 

reported side effects from using 

noni, its safety has not been 

adequately studied.

s There have been reports of 

liver damage from using noni. 

It should be avoided if you have 

liver disease because it contains 

compounds that may make your 

disease worse.

noni

Noni is an evergreen shrub or small tree that grows throughout the 

tropical regions of the Pacific Ocean, from Southeast Asia to Australia 

and especially in Polynesia. Noni has been traditionally used in 

Polynesia as a dye.
74 75

peppermint oil

The herb peppermint, a cross between two types of mint (water 

mint and spearmint), grows throughout Europe and North America. 

Peppermint is often used to flavor foods, and the leaves can be used 

fresh or dried in teas.

Common Name

peppermint oil

Latin Name

Mentha x piperita

What It Is Used For s Peppermint oil has been used for 

a variety of health conditions, 

including nausea, indigestion, 

and cold symptoms.

s Peppermint oil is also used for 

headaches, muscle and nerve 

pain, and stomach and bowel 

conditions such as irritable 

bowel syndrome.

How It Is Used

Essential oil of peppermint can be 

taken in very small doses in capsule 

or liquid forms. The essential oil 

can also be diluted with another oil 

and applied to the skin.

What the Science Says s Results from several studies 

suggest that peppermint oil may 

improve symptoms of irritable 

bowel syndrome.

s A few studies have found that 

peppermint oil, in combina-

tion with caraway oil, may help 

relieve indigestion, but this 

evidence is preliminary.

s Although there are some 

promising results, there is no 

clear-cut evidence to support the 

use of peppermint oil for other 

health conditions. 

Side Effects and Cautions s Peppermint oil appears to be safe 

for most adults when used in 

small doses. Possible side effects 

include allergic reactions and 

heartburn.

s Capsules containing peppermint 

oil are often coated to reduce the 

likelihood of heartburn. If they 

are taken at the same time as 

medicines such as antacids, this 

coating can break down more 

quickly and increase the risk 

of heartburn.
76 77

red clover

Like peas and beans, red clover belongs to the family of plants 

called legumes. Red clover contains phytoestrogens—compounds 

similar to the female hormone estrogen.

Common Names

red clover, cow clover, meadow clover, wild clover

Latin Name

Trifolium pratense

What It Is Used For

s Historically, red clover has been 

used for cancer and respiratory 

problems, such as whooping 

cough, asthma, and bronchitis.

s Current uses of red clover are for 

menopausal symptoms, breast 

pain associated with menstrual 

cycles, high cholesterol, osteoporosis, and symptoms of prostate 

enlargement.

How It Is Used

The flowering tops of the red clover 

plant are used to prepare extracts 

available in tablets and capsules, as 

well as in teas and liquid forms.

What the Science Says

s Several small studies of red clover 

for menopausal symptoms had 

mixed results; however, most of 

these studies had design flaws. 

A large clinical trial and several 

reviews of the research literature 

concluded that red clover had no 

significant beneficial effects on 

menopausal symptoms.

s There is not enough scientific 

evidence to determine whether 

red clover is effective for any 

other health conditions.

s NCCAM is studying red clover 

to learn more about its active 

components and how they 

might work in the body, including how red clover isoflavones 

may affect human prostate cells 

and the safety and effectiveness 

of red clover for menopausal 

symptoms.

Side Effects and Cautions

s Red clover seems to be safe 

for most adults when used 

for short periods of time. No 

serious adverse effects have 

been reported. 

s Because red clover contains 

estrogen-like compounds, there 

is a possibility that its long-term 

use would increase the risk of 

women developing cancer of the 

lining of the uterus. However, 

studies to date have been too 

brief (less than 6 months) to 

evaluate whether red clover 

has estrogen-like effects on 

the uterus.

s It is unclear whether red clover 

is safe for women who are 

pregnant or breastfeeding, or 

who have breast cancer or other 

hormone-sensitive cancers.
78 79

saw palmetto

Saw palmetto is a small palm tree native to the eastern United States. 

Its fruit was used medicinally by the Seminole Tribe of Florida.

Common Names

saw palmetto, American dwarf 

palm tree, cabbage palm

Latin Names

Serenoa repens, Sabal serrulata

What It Is Used For

s Saw palmetto is used mainly for 

urinary symptoms associated 

with an enlarged prostate gland 

(also called benign prostatic 

hyperplasia, or BPH).

s Saw palmetto is also used for 

other conditions, including 

chronic pelvic pain, bladder 

disorders, decreased sex drive, 

hair loss, hormone imbalances, 

and prostate cancer.

How It Is Used

The ripe fruit of saw palmetto is 

used in several forms, including 

ground and dried fruit or whole 

berries. It is available as liquid 

extracts, tablets, capsules, and as 

an infusion or a tea. 

What the Science Says

s Several small studies suggest 

that saw palmetto may be effective for treating BPH symptoms. 

However, a 2009 review of the 

research concluded that saw 

palmetto has not been shown to 

be more effective than placebo 

for this use.

s In 2006, a large study of 225 

men with moderate-to-severe 

BPH found no improvement 

with 320 mg saw palmetto 

daily for 1 year versus placebo. 

NCCAM cofunded the study 

with the National Institute of 

Diabetes and Digestive and 

Kidney Diseases.

s There is not enough scientific 

evidence to support the use of 

saw palmetto for reducing the 

size of an enlarged prostate or 

for any other conditions.

s Saw palmetto does not appear 

to affect readings of prostatespecific antigen (PSA) levels. 

PSA is protein produced by cells 

in the prostate. The PSA test is 

used to screen for prostate cancer 

and to monitor patients who 

have had prostate cancer.

s An NCCAM-funded study is 

looking at the effects of saw 

palmetto extract on prostate 

cancer cells.

Side Effects and Cautions

s Saw palmetto appears to be well 

tolerated by most users. It may 

cause mild side effects, including 

stomach discomfort. 
80 81

soy

Soy, a plant in the pea family, has been common in Asian diets for 

thousands of years. It is found in modern American diets as a food or 

food additive. Soybeans, the high-protein seeds of the soy plant, contain 

isoflavones—compounds similar to the female hormone estrogen. The 

following information highlights what is known about soy when used by 

adults for health purposes.

Common Name

soy

Latin Name

Glycine max

What It Is Used For

People use soy products to prevent 

or treat a variety of health conditions, including high cholesterol 

levels, menopausal symptoms 

such as hot flashes, osteoporosis, 

memory problems, high blood 

pressure, breast cancer, and 

prostate cancer.

How It Is Used

s Soy is available in dietary 

supplements, in forms such as 

tablets and capsules. Soy supplements may contain isoflavones 

or soy protein or both.

s Soybeans can be cooked and 

eaten or used to make tofu, soy 

milk, and other foods. Also, soy 

is sometimes used as an additive 

in various processed foods, 

including baked goods, cheese, 

and pasta.

What the Science Says

s Research suggests that daily 

intake of soy protein may 

slightly lower levels of LDL 

(“bad”) cholesterol.

s Some studies suggest that soy 

isoflavone supplements may 

reduce hot flashes in women 

after menopause. However, the 

results have been inconsistent.

s There is not enough scientific 

evidence to determine whether 

soy supplements are effective 

for any other health uses. 

s NCCAM supports studies 

on soy, including its effects 

in cardiovascular disease 

and breast cancer, and on 

menopause-related symptoms 

and bone loss.

Side Effects and Cautions

s Soy is considered safe for most 

people when used as a food or 

when taken for short periods as 

a dietary supplement. 

s Minor stomach and bowel 

problems such as nausea, 

bloating, and constipation 

are possible.

s Allergic reactions such as 

breathing problems and rash 

can occur in rare cases. 

s The safety of long-term use of 

soy isoflavones has not been 

established. Evidence is mixed on 

whether using isoflavone supplements over time can increase the 

risk of endometrial hyperplasia 

(a thickening of the lining of the 

uterus that can lead to cancer). 

Studies show no effect 

of dietary soy on risk for 

endometrial hyperplasia.

s Soy’s possible role in breast 

cancer risk is uncertain. Until 

more is known about soy’s effect 

on estrogen levels, women who 

have or who are at increased 

risk of developing breast cancer 

or other hormone-sensitive 

conditions (such as ovarian 

or uterine cancer) should be 

particularly careful about using 

soy and should discuss it with 

their health care providers.
82 83

st. john’s wort

St. John’s wort is a plant with yellow flowers whose medicinal uses were 

first recorded in ancient Greece. The name St. John’s wort apparently 

refers to John the Baptist, as the plant blooms around the time of the 

feast of St. John the Baptist in late June.

Common Names

St. John’s wort, hypericum, 

Klamath weed, goatweed

Latin Name

Hypericum perforatum

What It Is Used For

s St. John’s wort has been used for 

centuries to treat mental disorders and nerve pain.

s St. John’s wort has also been 

used as a sedative and a treatment for malaria, as well as a 

balm for wounds, burns, and 

insect bites. 

s Today, St. John’s wort is used 

by some for depression, anxiety, 

and/or sleep disorders.

How It Is Used

The flowering tops of St. John’s 

wort are used to prepare teas, 

tablets, and capsules containing concentrated extracts. Liquid 

extracts and topical preparations 

are also used.

What the Science Says

s There is scientific evidence that 

St. John’s wort may be useful 

for short-term treatment of 

mild to moderate depression. 

Although some studies have 

reported benefits for more severe 

depression, others have not; for 

example, a large study sponsored 

by NCCAM found that the 

herb was no more effective than 

placebo in treating major depression of moderate severity.

s NCCAM is studying the use 

of St. John’s wort in a wider 

spectrum of mood disorders, 

including minor depression.

Side Effects and Cautions

s St. John’s wort may cause 

increased sensitivity to sunlight. 

Other side effects can include 

anxiety, dry mouth, dizziness, 

gastrointestinal symptoms, 

fatigue, headache, or sexual 

dysfunction. 

s Research has shown that St. 

John’s wort interacts with many 

medications in ways that can 

interfere with their intended 

effects. Examples of medications 

that can be affected include:

Antidepressants

Birth control pills 

Cyclosporine, which prevents 

the body from rejecting transplanted organs 

Digoxin, a heart medication

Indinavir and possibly other 

drugs used to control HIV 

infection

Irinotecan and possibly other 

drugs used to treat cancer

Seizure-control drugs, such as 

dilantin and phenobarbital

Warfarin and related 

anticoagulants.

s Taking St. John’s wort with 

certain antidepressants may lead 

to increased serotonin-related 

side effects, which may be 

potentially serious.

s St. John’s wort is not a proven 

therapy for depression. If depression is not adequately treated, 

it can become severe. Anyone 

who may have depression should 

see a health care provider. There 

are effective proven therapies 

available. 
84 85

What It Is Used For

s Thunder god vine has been used 

in traditional Chinese medicine 

for conditions involving inflammation or overactivity of the 

immune system.

s Orally, thunder god vine is taken 

for excessive menstrual periods 

or for autoimmune diseases, 

including rheumatoid arthritis, 

multiple sclerosis, and lupus. 

s Thunder god vine preparations 

are also applied to the skin for 

rheumatoid arthritis.

How It Is Used

Extracts are prepared from the 

skinned root of thunder god vine.

What the Science Says

s Laboratory findings suggest 

that thunder god vine may fight 

inflammation, suppress the 

immune system, and have anticancer effects.

s Although early evidence is 

promising, there have been few 

high-quality studies of thunder 

god vine in people. Results from 

a large study funded by the 

National Institute of Arthritis 

and Musculoskeletal and Skin 

Diseases (NIAMS), which 

compared an extract of thunder 

god vine root with a conventional medicine (sulfasalazine) 

for rheumatoid arthritis, found 

that participants’ symptoms 

(e.g., joint pain and swelling, 

inflammation) improved more 

significantly with thunder god 

vine than with sulfasalazine.

Common Names

thunder god vine, 

lei gong teng

Latin Name

Tripterygium wilfordii

s A small study on thunder god 

vine applied to the skin also 

found benefits for rheumatoid 

arthritis symptoms.

s There is not enough scientific 

evidence to assess thunder 

god vine’s use for any other 

health conditions.

Side Effects and Cautions

s Thunder god vine can cause 

severe side effects and can be 

poisonous if it is not carefully 

extracted from the skinned 

root. Other parts of the plant—

including the leaves, flowers, 

and skin of the root—are highly 

poisonous and can cause death.

s A number participants in the 

NIAMS study experienced 

gastrointestinal adverse effects 

such as diarrhea, indigestion, and 

nausea, as well as upper respiratory tract infections. (The rate 

of adverse effects was similar in 

both the thunder god vine and 

sulfasalazine groups.)

s Thunder god vine can also cause 

hair loss, headache, menstrual 

changes, and skin rash.

s There are no consistent, highquality thunder god vine 

products being manufactured in 

the United States. Preparations 

of thunder god vine made 

outside the United States 

(for example, in China) can 

sometimes be obtained, but it 

is not possible to verify whether 

they are safe and effective.

s Thunder god vine has been 

found to decrease bone mineral 

density in women who take the 

herb for 5 years or longer. This 

side effect may be of particular 

concern to women who have 

osteoporosis or are at risk for 

the condition.

s Thunder god vine contains 

chemicals that might decrease 

male fertility by changing sperm.

thunder god vine

Thunder god vine is a perennial vine native to China, Japan, and Korea. 

It has been used in China for health purposes for more than 400 years.
86 87

turmeric

Turmeric, a shrub related to ginger, is grown throughout India, other 

parts of Asia, and Africa. Known for its warm, bitter taste and golden 

color, turmeric is commonly used in fabric dyes and foods such as 

curry powders, mustards, and cheeses. It should not be confused with 

Javanese turmeric.

Common Names

turmeric, turmeric root, 

Indian saffron

Latin Name

Curcuma longa

What It Is Used For

s In traditional Chinese medicine 

and Ayurvedic medicine, 

turmeric has been used to aid 

digestion and liver function, 

relieve arthritis pain, and 

regulate menstruation.

s Turmeric has also been applied 

directly to the skin for eczema 

and wound healing.

s Today, turmeric is used for 

conditions such as heartburn, 

stomach ulcers, and gallstones. 

It is also used to reduce inflammation, as well as to prevent and 

treat cancer.

How It Is Used

Turmeric’s finger-like underground 

stems (rhizomes) are dried and 

taken by mouth as a powder or in 

capsules, teas, or liquid extracts. 

Turmeric can also be made into a 

paste and used on the skin.

What the Science Says

s There is little reliable evidence 

to support the use of turmeric 

for any health condition because 

few clinical trials have been 

conducted.

s Preliminary findings from 

animal and laboratory studies 

suggest that a chemical found in 

turmeric—called curcumin—may 

have anti-inflammatory, anticancer, and antioxidant properties, 

but these findings have not been 

confirmed in people.

s NCCAM-funded investigators 

have studied the active chemicals 

in turmeric and their effects—

particularly anti-inflammatory 

effects—in human cells to better 

understand how turmeric might 

be used for health purposes. 

NCCAM is also funding basic 

research studies on the potential 

role of turmeric in preventing acute respiratory distress 

syndrome, liver cancer, and 

post-menopausal osteoporosis.

Side Effects and Cautions

s Turmeric is considered safe for 

most adults.

s High doses or long-term use of 

turmeric may cause indigestion, 

nausea, or diarrhea. 

s In animals, high doses of 

turmeric have caused liver 

problems. No cases of liver 

problems have been reported 

in people. 

s People with gallbladder disease 

should avoid using turmeric as 

a dietary supplement, as it may 

worsen the condition.
88 89

valerian

Valerian is a plant native to Europe and Asia; it is also found in North 

America. Valerian has been used as a medicinal herb since at least 

the time of ancient Greece and Rome. Its therapeutic uses were 

described by Hippocrates, and in the 2nd century, Galen prescribed 

valerian for insomnia.

Common Names

valerian, all-heal, garden heliotrope

Latin Name

Valeriana officinalis

What It Is Used For s Valerian has long been used for 

sleep disorders and anxiety.

s Valerian has also been used 

for other conditions, such as 

headaches, depression, irregular 

heartbeat, and trembling.

How It Is Used

The roots and rhizomes (under-

ground stems) of valerian are 

typically used to make supple-

ments, including capsules, tablets, 

and liquid extracts, as well as teas.

What the Science Says s Research suggests that valerian 

may be helpful for insomnia, 

but there is not enough evidence 

from well-designed studies to 

confirm this.

s There is not enough scientific 

evidence to determine whether 

valerian works for other 

conditions, such as anxiety or 

depression.

s NCCAM-funded research on 

valerian includes studies on the 

herb’s effects on sleep in healthy 

older adults and in people with 

Parkinson’s disease. NCCAMfunded researchers are also 

studying the potential of valer-

ian and other herbal products to 

relieve menopausal symptoms.

Side Effects and Cautions s Studies suggest that valerian is 

generally safe to use for short 

periods of time (for example, 

4 to 6 weeks).

s No information is available 

about the long-term safety 

of valerian.

s Valerian can cause mild side 

effects, such as headaches, dizzi-

ness, upset stomach, and tiredness 

the morning after its use.
91

What It Is Used For

s Yohimbe bark has traditionally 

been used in Africa as an aphrodisiac (to increase sexual desire).

s The herb is currently used for 

sexual dysfunction, including 

erectile dysfunction in men.

How It Is Used

As a dietary supplement, the dried 

bark of the yohimbe tree is used 

as a tea and taken by mouth. An 

extract of the bark is also put into 

capsules and tablets.

Common Names

yohimbe, yohimbe bark

Latin Name

Pausinystalia yohimbe

90

What the Science Says

It is not known whether yohimbe 

is effective for any health conditions because clinical trials have 

not been conducted on the bark 

or its extract.

Side Effects and Cautions

s Yohimbe has been associated with 

high blood pressure, increased 

heart rate, headache, anxiety, 

dizziness, nausea, vomiting, 

tremors, and sleeplessness. 

Yohimbe can be dangerous if 

taken in large doses or for long 

periods of time.

s People should not combine 

yohimbe with MAO inhibitors as 

effects may be additive. Yohimbe 

should be used with caution when 

taken with medicines for high 

blood pressure, tricyclic antidepressants, or phenothiazines (a 

group of medicines used mostly 

for mental health conditions such 

as schizophrenia).

s People with kidney problems and 

people with psychiatric conditions should not use yohimbe.

s Women who are pregnant or 

breastfeeding should not take 

yohimbe.

The yohimbe tree is a tall evergreen that is native to western Africa. 

The bark of the tree contains a chemical called yohimbine. The 

amount of yohimbine in dietary supplements may vary; some 

yohimbe products have been found to contain very little yohimbine. 

A drug form of yohimbine—yohimbine hydrochloride—has been 

studied for erectile dysfunction.

yohimbe
92 93

standard

references

Encyclopedia of Dietary Supplements. New York, NY: 

Marcel Dekker; 2005. 

Herbal Medicine: Expanded Commission E Monographs. 

Newton, MA: Lippincott Williams & Wilkins; 2000. 

Natural Medicines Comprehensive Database Web site. 

Accessed at www.naturaldatabase.com.

Natural Standard Database Web site. Accessed at 

www.naturalstandard.com.

additional

references for

specific herbs

Bitter Orange

Bent S, Padula A, Neuhaus J. Safety and efficacy of citrus aurantium for 

weight loss. American Journal of Cardiology. 2004;94(10):1359-1361.

U.S. Food and Drug Administration. FDA Requests Seizure of 

More Dietary Supplements Containing Ephedrine Alkaloids. U.S. 

Food and Drug Administration Web site. Accessed at www.fda.gov/

NewsEvents/Newsroom/PressAnnouncements/2006/ucm108606.htm

on June 3, 2010.

Black Cohosh

Borrelli F, Ernst E. Black cohosh for menopausal symptoms: a system-

atic review of its efficacy. Pharmacological Research. 2008;58(1):8-14.

Borrelli F, Ernst E. Black cohosh for menopausal symptoms: a 

systematic review of its safety. American Journal of Obstetrics & 

Gynecology. 2008;199(5):455-466.

Mahady GB, Low Dog T, Barrett ML, et al. United States 

Pharmacopeia review of the black cohosh case reports of 

hepatotoxicity. Menopause. 2008;15(4 Pt 1):628-638.

National Center for Complementary and Alternative Medicine and 

Office of Dietary Supplements. Workshop on the Safety of Black 

Cohosh in Clinical Studies. National Center for Complementary and 

Alternative Medicine Web site. Accessed at nccam.nih.gov/news/

events/blackcohosh/blackcohosh_mtngsumm.htm on June 3, 2010.

Newton KM, Reed SD, LaCroix AZ, et al. Treatment of vasomotor 

symptoms of menopause with black cohosh, multibotanicals, soy, 

hormone therapy, or placebo: a randomized trial. Annals of Internal 

Medicine. 2006;145(12):869-879. 

Office of Dietary Supplements. Dietary Supplement Fact Sheet: 

Black Cohosh. Office of Dietary Supplements Web site. Accessed at 

ods.od.nih.gov/factsheets/blackcohosh.asp on June 3, 2010.
94 95

Cranberry

Jepson RG, Craig JC. Cranberries for preventing urinary tract infec-

tions. Cochrane Database of Systematic Reviews. 2008;(1):CD001321. 

Echinacea

Barrett BP, Brown RL, Locken K, et al. Treatment of the common 

cold with unrefined echinacea: a randomized, double-blind, placebocontrolled trial. Annals of Internal Medicine. 2002;137(12):939-946.

Fugh-Berman A. Echinacea for the prevention and treatment of 

upper respiratory infections. Seminars in Integrative Medicine.

2003;1(2):106-111.

O’Neil J, Hughes S, Lourie A, et al. Effects of echinacea on the 

frequency of upper respiratory tract symptoms: a randomized, 

double-blind, placebo-controlled trial. Annals of Allergy, Asthma, 

and Immunology. 2008;100(4):384-388.

Shah SA, Sander S, White CM, et al. Evaluation of echinacea for 

the prevention and treatment of the common cold: a meta-analysis. 

Lancet Infectious Diseases. 2007;7(7):473-480.

Taylor JA, Weber W, Standish L, et al. Efficacy and safety of 

echinacea in treating upper respiratory tract infections in children: 

a randomized controlled trial. Journal of the American Medical 

Association. 2003;290(21):2824-2830.

Turner RB, Bauer R, Woelkart K, et al. An evaluation of Echinacea 

angustifolia in experimental rhinovirus infections. New England 

Journal of Medicine. 2005;353(4):341-348.

Ephedra

National Center for Complementary and Alternative Medicine. 

Ephedra. National Center for Complementary and Alternative 

Medicine Web site. Accessed at nccam.nih.gov/news/alerts/

ephedra/consumeradvisory.htm on June 3, 2010.

European Mistletoe

Horneber M, Bueschel G, Huber R, et al. Mistletoe therapy in oncol-

ogy. Cochrane Database of Systematic Reviews. 2008;(2):CD003297. 

National Cancer Institute. Mistletoe Extracts (PDQ). National Cancer 

Institute Web site. Accessed at www.cancer.gov/cancerinfo/pdq/

cam/mistletoe on June 3, 2010.

Flaxseed and Flaxseed Oil

Pan A, Yu D, Demark-Wahnefried W. Meta-analysis of the effects of 

flaxseed interventions on blood lipids. American Journal of Clinical 

Nutrition. 2009;90(2):288-297.

Garlic

Agency for Healthcare Research and Quality. Garlic: Effects on 

Cardiovascular Risks and Disease, Protective Effects Against 

Cancer, and Clinical Adverse Effects. Evidence Report/Technology 

Assessment no. 20. Rockville, MD: Agency for Healthcare Research 

and Quality; 2000. AHRQ publication no. 01-E023.

Gardner CD, Lawson LD, Block E, et al. Effect of raw garlic vs. 

commercial garlic supplements on plasma lipid concentrations in 

adults with moderate hypercholesterolemia: a randomized clinical 

trial. Archives of Internal Medicine. 2007;167(4):346-353.

National Cancer Institute. Garlic and Cancer Prevention: Questions 

and Answers. National Cancer Institute Web site. Accessed at 

www.cancer.gov/cancertopics/factsheet/Prevention/garlic-and-cancerprevention on June 3, 2010.

Ginkgo

Brinkley TE, Lovato JF, Arnold AM, et al. Effect of Ginkgo biloba

on blood pressure and incidence of hypertension in elderly men and 

women. American Journal of Hypertension. 2010; 23(5): 528-533.

DeKosky ST, Williamson JD, Fitzpatrick AL, et al. Ginkgo biloba for 

prevention of dementia: a randomized controlled trial. Journal of the 

American Medical Association. 2008;300(19):2253-2262.

Snitz BE, O’Meara ES, Carlson MC, et al. Ginkgo biloba for 

preventing cognitive decline in older adults: a randomized trial. Journal

of the American Medical Association. 2009;302(24):2663-2670.

Solomon PR, Adams F, Silver A, et al. Ginkgo for memory 

enhancement: a randomized controlled trial. Journal of the 

American Medical Association. 2002;288(7):835-840.

Grape Seed Extract

Brooker S, Martin S, Pearson A, et al. Double-blind, placebo-controlled, 

randomised phase II trial of IH636 grape seed proanthocyanidin 

extract (GSPE) in patients with radiation-induced breast induration. 

Radiotherapy and Oncology. 2006;79(1):45-51.

Green Tea

National Cancer Institute. Tea and Cancer Prevention. National 

Cancer Institute Web site. Accessed at www.cancer.gov/newscenter/

pressreleases/tea on June 3, 2010.

Sarma DN, Barrett ML, Chavez ML, et al. Safety of green tea 

extracts: a systematic review by the US Pharmacopeia. Drug Safety. 

2008;31(6):469-484.
96 97

Kava

National Center for Complementary and Alternative Medicine. Kava 

Linked to Liver Damage. National Center for Complementary and 

Alternative Medicine Web site. Accessed at nccam.nih.gov/news/

alerts/kava/ on June 3, 2010.

U.S. Food and Drug Administration. Kava-Containing Dietary 

Supplements May Be Associated With Severe Liver Injury. U.S. Food 

and Drug Administration Web site. Accessed at www.fda.gov/Food/

ResourcesForYou/Consumers/ucm085482.htm on June 3, 2010.

Lavender

Henley DV, Lipson N, Korach KS, et al. Prepubertal gynecomastia 

linked to lavender and tea tree oils. New England Journal of Medicine.

2007;356(5):479-485.

Licorice Root

National Center for Complementary and Alternative Medicine. 

CAM and Hepatitis C: A Focus on Herbal Supplements. National 

Center for Complementary and Alternative Medicine Web site. 

Accessed at nccam.nih.gov/health/hepatitisc/ on June 3, 2010.

Milk Thistle

Agency for Healthcare Research and Quality. Milk Thistle: Effects 

on Liver Disease and Cirrhosis and Clinical Adverse Effects. Evidence 

Report/Technology Assessment no. 21. Rockville, MD: Agency 

for Healthcare Research and Quality; 2000. AHRQ publication 

no. 01-E025.

National Center for Complementary and Alternative Medicine. CAM 

and Hepatitis C: A Focus on Herbal Supplements. National Center 

for Complementary and Alternative Medicine Web site. Accessed at 

nccam.nih.gov/health/hepatitisc/ on June 3, 2010.

Noni

Mueller BA, Scott MK, Sowinski KM, et al. Noni juice (Morinda 

citrifolia): hidden potential for hyperkalemia? American Journal of 

Kidney Disease. 2000;35(2):310-312.

Red Clover

Fugh-Berman A, Kronenberg F. Red clover (Trifolium pratense) 

for menopausal women: current state of knowledge. Menopause. 

2001;8(5):333-337.

Lethaby AE, Brown J, Marjoribanks J, et al. Phytoestrogens for 

vasomotor menopausal symptoms. Cochrane Database Systematic 

Reviews. 2007;(4):CD001395.

Nelson HD, Vesco KK, Haney E, et al. Nonhormonal therapies for 

menopausal hot flashes: systematic review and meta-analysis. Journal 

of the American Medical Association. 2006;295(17):2057-2071.

Tice JA, Ettinger B, Ensrud K, et al. Phytoestrogen supplements for 

the treatment of hot flashes: the Isoflavone Clover Extract (ICE) study. 

Journal of the American Medical Association. 2003;290(2):207-214.

Saw Palmetto

Bent S, Kane C, Shinohara K, et al. Saw palmetto for benign prostatic 

hyperplasia. New England Journal of Medicine. 2006;354(6):557-566.

National Cancer Institute. The Prostate-Specific Antigen (PSA) Test: 

Questions and Answers. National Cancer Institute Web site. Accessed at 

www.cancer.gov/cancertopics/factsheet/Detection/PSA on June 3, 2010.

Soy

Balk E, Chung M, Chew P, et al. Effects of Soy on Health Outcomes.

Evidence Report/Technology Assessment no. 126. Rockville, MD: 

Agency for Healthcare Research and Quality; 2005. AHRQ 

publication no. 05-E024-1.

Low Dog T. Menopause: a review of botanical dietary supplements. 

American Journal of Medicine. 2005;118(suppl 12B):98S-108S. 

Sacks FM, Lichtenstein A, Van Horn L, et al. Soy protein, 

isoflavones, and cardiovascular health: an American Heart Association 

Science Advisory for professionals from the Nutrition Committee. 

Circulation. 2006;113(7):1034-1044. 

St. John’s Wort

De Smet PA. Herbal remedies. New England Journal of Medicine.

2002;347(25):2046-2056.

Hypericum Depression Trial Study Group. Effect of Hypericum 

perforatum (St. John’s wort) in major depressive disorder: a 

randomized controlled trial. Journal of the American Medical 

Association. 2002;287(14):1807-1814.

National Center for Complementary and Alternative Medicine. 

St. John’s Wort and Depression. National Center for Complementary 

and Alternative Medicine Web site. Accessed at nccam.nih.gov/health/

stjohnswort/sjw-and-depression.htm on June 3, 2010.
98 99

Thunder God Vine

Canter PH, Hyang SL, Ernst E. A systematic review of random-

ized clinical trials of Tripterygium wilfordii for rheumatoid arthritis. 

Phytomedicine. 2006;13(5):371-377.

Carter BZ, Mark DH, Schober WD, et al. Triptolide induces 

caspase-dependent cell death mediated via the mitochondrial 

pathway in leukemic cells. Blood. 2006;108(2):630-637.

Goldbach-Manksy R, Wilson M, Fleischmann R, et al. Comparison of 

Tripterygium wilfordii Hook F versus sulfasalazine in the treatment of 

rheumatoid arthritis: a randomized trial. Annals of Internal Medicine. 

2009;151(4):229-240, W49-51.

National Center for Complementary and Alternative Medicine. 

Rheumatoid Arthritis and CAM. National Center for Complementary 

and Alternative Medicine Web site. Accessed at nccam.nih.gov/health/

RA/ on June 3, 2010.

National Institute of Arthritis and Musculoskeletal and Skin Diseases. 

Chinese Thunder God Vine Gives Relief from Rheumatoid Arthritis 

Symptoms. National Institute of Arthritis and Musculoskeletal and 

Skin Diseases Web site. Accessed at www.niams.nih.gov/News_and_

Events/Spotlight_on_Research/2002/thunder.asp on June 3, 2010.

Setty AR, Sigal LH. Herbal medications commonly used in the 

practice of rheumatology: mechanisms of action, efficacy, and side 

effects. Seminars in Arthritis and Rheumatism. 2005;34(6):773-784.

Tao X, Younger J, Fan FZ, et al. Benefit of an extract of Tripterygium 

wilfordii Hook F in patients with rheumatoid arthritis: a double-blind, 

placebo-controlled study. Arthritis & Rheumatism. 2002;46(7):1735-1743.

Valerian

Office of Dietary Supplements and National Center for 

Complementary and Alternative Medicine. Questions and Answers 

About Valerian for Insomnia and Other Sleep Disorders. Office of 

Dietary Supplements Web site. Accessed at ods.od.nih.gov/factsheets/

valerian.asp on June 3, 2010.

index of common

and scientific names a

Actaea racemosa, 18

Aesculus 

hippocastanum, 62

all-heal, 88

Allium sativum, 46

aloe, 8

Aloe barbadensis, 8

Aloe vera, 8

American coneflower, 30

American cranberry, 26

American dwarf

palm tree, 78

Asian ginseng, 10

Asiatic ginseng, 10

astragalus, 12

Astragalus 

membranaceus, 12

Astragalus 

mongholicus, 12

awa, 64

b 

bachelor’s buttons, 42

bai guo ye, 50

baiguo, 50

bei qi, 12

bilberry, 14

bitter orange, 16

black cohosh, 18

black elder, 34

black snakeroot, 18

blowball, 28

bog cranberry, 26

buckeye, 62

bugbane, 18

bugwort, 18

burn plant, 8

c

cabbage palm, 78

Camellia sinensis, 56

canary wood, 72

cat’s claw, 20

chamomile, 22

Chamomilla recutita, 22

chasteberry, 24

chaste-tree berry, 24

Chinese ephedra, 32

Chinese ginseng, 10

Chinese licorice, 68

Chinese tea, 56

Chrysanthemum 

parthenium, 42

Cimicifuga racemosa, 18

Citrus aurantium, 16

coneflower, 30

cow clover, 76

cranberry, 26

Crataegus laevigata, 58

Crataegus 

monogyna, 58

Crataegus 

oxyacantha, 58

Curcuma longa, 86

d 

dandelion, 28 e

echinacea, 30

Echinacea 

angustifolia, 30

Echinacea pallida, 30

Echinacea purpurea, 30

elder, 34

elder flower, 34

elderberry, 34

elephant’s gall, 8

English hawthorn, 58

English lavender, 66

ephedra, 32

Ephedra sinica, 32

EPO, 38

European blueberry, 14

European elder, 34

European mistletoe, 36

evening primrose oil, 38

f 

featherfew, 42

fenugreek, 40

fenugreek seed, 40

feverfew, 42

flaxseed, 44

flaxseed oil, 44

fossil tree, 50

g 

gan zao (Chinese

licorice), 68

garden heliotrope, 88

garden lavender, 66

garlic, 46

German chamomile, 22

ginger, 48

ginkgo, 50

Ginkgo biloba, 50

ginseng, 10

Glycine max, 80 

Glycyrrhiza glabra, 68

Glycyrrhiza 

uralensis, 68

goatweed, 82

goldenseal, 52

grape seed extract, 54

green tea, 56
101

h

harthorne, 58

haw, 58

hawthorn, 58

hawthorne, 58

hog apple, 72

holy thistle, 70

hoodia, 60

Hoodia gordonii, 60

horse chestnut, 62

huang qi, 12

huckleberry, 14

hwanggi, 12

Hydrastis canadensis, 52

hypericum, 82

Hypericum perforatum, 82 i

Indian mulberry, 72

Indian saffron, 86

j 

Japanese silver 

apricot, 50

Japanese tea, 56 k

Kalahari cactus, 60

kava, 64

kava kava, 64

kava pepper, 64

kew tree, 50

Klamath weed, 82

Korean ginseng, 10 l

Lavandula angustifolia, 66

lavender, 66

lei gong teng, 84

licorice, 68

licorice root, 68

lily of the desert, 8

linseed, 44

Linum 

usitatissimum, 44

lion’s tooth, 28

liquorice, 68

m

ma huang, 32

macrotys, 18

maidenhair tree, 50

Mary thistle, 70

Matricaria recutita, 22

meadow clover, 76

Mentha x piperita, 74

milk thistle, 70

milk vetch, 12

mistletoe, 36

monk’s pepper, 24

morinda, 72

Morinda citrifolia, 72 n

noni, 72 o

Oenothera biennis, 38

ogi, 12 p

Panax ginseng, 10

Pausinystalia 

yohimbe, 90

peppermint oil, 74

Piper methysticum, 64

purple coneflower, 30 r

rattleroot, 18

rattleweed, 18

red clover, 76

s 

Sabal serrulata, 78

sambucus, 34

Sambucus nigra, 34

saw palmetto, 78

Serenoa repens, 78

Seville orange, 16

silibinin, 70

silybin, 70

silybinin, 70

Silybum marianum, 70

silymarin, 70

sour orange, 16

soy, 80

Spanish chestnut, 62

St. John’s wort, 82

sweet root, 68 t

Tanacetum parthenium, 42

Taraxacum officinale, 28

thunder god vine, 84

Trifolium pratense, 76

Trigonella 

foenum-graecum, 40

Tripterygium 

wilfordii, 84

turmeric, 86

turmeric root, 86 u

uña de gato, 20

Uncaria guianensis, 20

Uncaria tomentosa, 20

v 

Vaccinium macrocarpon, 26

Vaccinium myrtillus, 14

valerian, 88

Valeriana officinalis, 88

Viscum album L., 36

vitex, 24

Vitex agnus-castus, 24

Vitis vinifera, 54 w

whortleberry, 14

wild clover, 76 x

Xhoba, 60 y

yellow root, 52

yinhsing (yin-hsing), 50

yohimbe, 90

yohimbe bark, 90 z

Zhi shi, 16

Zingiber officinale, 48

100

index of health

conditions/uses

This index is based on health conditions mentioned in the “What the 

Science Says” summaries for each herb. These summaries will give 

you an idea of what is known—and not known—about the effective-

ness of various herbs for the conditions listed. Please note that this 

index focuses only on conditions that these herbs are used to treat or 

prevent. Mentions of an herb’s use for various health conditions are 

not intended as an endorsement or recommendation from NCCAM. a

abrasions, 8

alopecia areata, 66

Alzheimer’s 

disease, 50

anxiety, 64, 66, 88

atherosclerosis, 46 b

benign prostatic 

hyperplasia (BPH), 78

blood pressure 

control, 46, 50

breast cancer, 54

breast pain, 24, 38

burns, 8 c

cancer, 12, 36, 44, 46, 56,

72, 84, 86

cholesterol 

control, 44, 46, 56, 80

cognitive decline, 50

colds, 30

colic, 22

d

dementia, 50

dental plaque 

prevention, 26

depression, 82, 88

diabetes, 40, 54

diabetic retinopathy, 54 

diarrhea, 22, 52 e

eczema, 38

edema, 54

eye infection, 52 f

flu, 34 g

glucose control, 10 h

hair loss (from 

alopecia areata), 66

headache, 42

heart disease, 44, 58

hepatitis C, 68, 70

hot flashes, 18, 44, 80

hypertension, 50 i

immune function, 10, 

12, 20, 36, 72, 84

infertility, 24

inflammation, 20, 84, 86

insomnia, 88

intermittent claudication

(leg pain), 50

irritable bowel

syndrome, 74

j

joint pain, 48, 84 l

laxative, 8, 44

liver disease, 70
m

memory 

enhancement, 50

menopausal 

symptoms, 18, 38, 76

mental alertness, 56

migraine headaches, 42

mouth ulcers, 22

muscle pain, 48

n

nausea/vomiting, 48 

night sweats, 18

night vision, 14

o

osteoarthritis, 20, 48

p

premenstrual 

syndrome, 24, 38

prostate, enlarged, 78

r

respiratory tract 

infections, 30

rheumatoid arthritis, 

20, 38, 42, 48, 84

s

sexual dysfunction (due 

to antidepressants), 50

sinus infection, 34

skin conditions, 22

skin protection from 

sun damage, 56

stomach ache (upset

stomach/indigestion), 

22, 74

stomach cancer, 46

stomach ulcer, 26

t

tinnitus, 50

u

urinary tract infection, 26

v

vascular fragility, 54

venous insufficiency

(chronic), 54, 62

w

weight loss, 16, 32, 56

wounds, 8

102
U.S. Department of Health

and Human Services

National Institutes of Health

National Center for Complementary 

and Alternative Medicine

D401

NIH Publication No. 10-6248

Revised June 2010