Homeopathy: An Introduction

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Homeopathy, also known as homeopathic medicine, is an 

alternative medical system that was developed in Germany more 

than 200 years ago. This fact sheet provides a general overview of 

homeopathy and suggests sources for additional information.

Key Points 

• There is little evidence to support homeopathy as an effective 

treatment for any specific condition.

• Although people sometimes assume that all homeopathic 

remedies are highly diluted and therefore unlikely to cause 

harm, some products labeled as homeopathic can contain 

substantial amounts of active ingredients and therefore could 

cause side effects and drug interactions.

• Homeopathic remedies are regulated by the U.S. Food and Drug 

Administration (FDA). However, FDA does not evaluate the 

remedies for safety or effectiveness.

• Several key concepts of homeopathy are inconsistent with 

fundamental concepts of chemistry and physics. There are 

significant challenges in carrying out rigorous clinical research 

on homeopathic remedies.

• Tell all your health care providers about any complementary 

health approaches you use. Give them a full picture of all you do 

to manage your health. This will help ensure coordinated and 

safe care.

Overview 

The alternative medical system of homeopathy was developed in 

Germany at the end of the 18th century. Supporters of homeopathy 

point to two unconventional theories: “like cures like”—the notion

that a disease can be cured by a substance that produces similar

symptoms in healthy people; and “law of minimum dose”—the 

notion that the lower the dose of the medication, the greater its 

effectiveness. Many homeopathic remedies are so diluted that no 

molecules of the original substance remain.

U.S. DEPARTMENT OF HEALTH 

AND HUMAN SERVICES

National Institutes of Health

National Center for Complementary 

and Alternative Medicine
Homeopathic remedies are derived from substances that come from plants, minerals, or 

animals, such as red onion, arnica (mountain herb), crushed whole bees, white arsenic, poison 

ivy, belladonna (deadly nightshade), and stinging nettle. Homeopathic remedies are often 

formulated as sugar pellets to be placed under the tongue; they may also be in other forms, 

such as ointments, gels, drops, creams, and tablets. Treatments are “individualized” or tailored 

to each person—it is not uncommon for different people with the same condition to receive 

different treatments.

Use in the United States 

According to the 2007 National Health Interview Survey, which included a comprehensive 

survey on the use of complementary health practices by Americans, an estimated 3.9 million 

adults and 910,000 children used homeopathy in the previous year. These estimates included 

use of over-the-counter products labeled as “homeopathic,” as well as visits with a 

homeopathic practitioner. Out-of-pocket costs for adults were $2.9 billion for homeopathic 

medicines and $170 million for visits to homeopathic practitioners.

The Status of Homeopathy Research 

Most rigorous clinical trials and systematic analyses of the research on homeopathy have 

concluded that there is little evidence to support homeopathy as an effective treatment for any 

specific condition.

Homeopathy is a controversial topic in complementary health research. A number of the key 

concepts of homeopathy are not consistent with fundamental concepts of chemistry and 

physics. For example, it is not possible to explain in scientific terms how a remedy containing 

little or no active ingredient can have any effect. This, in turn, creates major challenges to 

rigorous clinical investigation of homeopathic remedies. For example, one cannot confirm that 

an extremely dilute remedy contains what is listed on the label, or develop objective measures 

that show effects of extremely dilute remedies in the human body.

Another research challenge is that homeopathic treatments are highly individualized, and 

there is no uniform prescribing standard for homeopathic practitioners. There are hundreds of 

different homeopathic remedies, which can be prescribed in a variety of different dilutions for 

thousands of symptoms.

Side Effects and Risks 

• Certain homeopathic products (called “nosodes” or “homeopathic immunizations”) have 

been promoted by some as substitutes for conventional immunizations, but data to support 

such claims are lacking. The National Center for Complementary and Alternative Medicine 

(NCCAM) supports the Centers for Disease Control and Prevention’s recommendations for 

immunizations/vaccinations. To learn more about vaccines visit www.vaccines.gov. 

• While many homeopathic remedies are highly diluted, some products sold or labeled as 

homeopathic may not be highly diluted; they may contain substantial amounts of active 

ingredients. Like any drug or dietary supplement that contains chemical ingredients, these 

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homeopathic products may cause side effects or drug interactions. Negative health effects 

from homeopathic products of this type have been reported.

• A 2007 systematic review found that highly diluted homeopathic remedies, taken under 

the supervision of trained professionals, are generally safe and unlikely to cause severe 

adverse reactions. However, like any drug or dietary supplement, these products could 

pose risks if they are improperly manufactured (for example, if they are contaminated with 

microorganisms or incorrectly diluted).

• A 2012 systematic review of case reports and case series concluded that using certain 

homeopathic treatments (such as those containing heavy metals like mercury or iron that 

are not highly diluted) or replacing an effective conventional treatment with an ineffective 

homeopathic one can cause adverse effects, some of which may be serious.

• Liquid homeopathic remedies may contain alcohol. The FDA allows higher levels of alcohol 

in these remedies than it allows in conventional drugs.

• Homeopathic practitioners expect some of their patients to experience “homeopathic 

aggravation” (a temporary worsening of existing symptoms after taking a homeopathic 

prescription). Researchers have not found much evidence of this reaction in clinical 

studies; however, research on homeopathic aggravations is scarce. Always discuss changes 

in your symptoms with your health care provider.

Regulation of Homeopathic Treatments 

Homeopathic remedies are regulated as drugs under the Federal Food, Drug and Cosmetic Act 

(FDCA). However, under current Agency policy, FDA does not evaluate the remedies for safety or 

effectiveness. FDA enforcement policies for homeopathic drugs are described in FDA’s Compliance 

Policy Guide entitled Conditions Under Which Homeopathic Drugs May be Marketed (CPG 7132.15).

FDA allows homeopathic remedies that meet certain conditions to be marketed without 

agency preapproval. For example, homeopathic remedies must contain active ingredients that 

are listed in the Homeopathic Pharmacopeia of the United States (HPUS). The HPUS lists active 

ingredients that may be legally included in homeopathic products and standards for strength, 

quality, and purity of that ingredient. In addition, the FDA requires that the label on the 

product, outer container, or accompanying leaflet include at least one major indication (i.e., 

medical problem to be treated), a list of ingredients, the number of times the active ingredient 

was diluted, and directions for use. If a homeopathic remedy claims to treat a serious disease 

such as cancer, it must be sold by prescription. Only products for minor health problems, like a 

cold or headache, which go away on their own, can be sold without a prescription.

Licensing 

Laws regulating the practice of homeopathy in the United States vary from state to state. 

Usually, individuals who are licensed to practice medicine or another health care 

profession can legally practice homeopathy. In some states, non-licensed professionals 

may practice homeopathy.

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Arizona, Connecticut, and Nevada are the only states with homeopathic licensing boards 

for doctors of medicine (holders of M.D. degrees) and doctors of osteopathic medicine 

(holders of D.O. degrees). Arizona and Nevada also license homeopathic assistants, who are 

allowed to perform medical services under the supervision of a homeopathic physician. 

Some states explicitly include homeopathy within the scope of practice of chiropractic, 

naturopathy, and physical therapy.

If You Are Thinking About Using Homeopathy 

• Do not use homeopathy to replace conventional care or to postpone seeing your health 

care provider about a medical problem.

• If you are considering using a homeopathic remedy, bring the product with you when you 

visit your health care provider. The provider may be able to help you determine whether 

the product might pose a risk of side effects or drug interactions.

• Follow the recommended conventional immunization schedules for children and adults. 

Do not use homeopathic products as substitutes for conventional immunizations.

• Women who are pregnant or nursing, or people who are thinking of using homeopathy to 

treat a child, should consult their (or their child’s) health care providers.

• Tell all your health care providers about any complementary health approaches you use. 

Give them a full picture of all you do to manage your health. This will ensure coordinated 

and safe care. For tips about talking with your health care providers about complementary 

health approaches, see NCCAM’s Time to Talk campaign at nccam.nih.gov/timetotalk. 

Selected References 

Altunc U, Pittler MH, Ernst E. Homeopathy for childhood and adolescence ailments: systematic review of randomized 

clinical trials. Mayo Clinic Proceedings. 2007;82(1):69-75.

Cucherat M, Haugh MC, Gooch M, et al. Evidence of clinical efficacy of homeopathy: a meta-analysis of clinical trials. 

European Journal of Clinical Pharmacology. 2000;56(1):27-33.

Der Marderosian AH. Understanding homeopathy. Journal of the American Pharmaceutical Association. 1996;NS36(5):317-321.

Ernst E. A systematic review of systematic reviews of homeopathy. British Journal of Clinical Pharmacology. 

2002;54(6):577-582.

Ernst E. Homeopathy: what does the “best” evidence tell us? Medical Journal of Australia. 2010;192(8):458-460.

Ernst E. The truth about homeopathy. British Journal of Clinical Pharmacology. 2007;65(2):163-164.

Jonas WB, Kaptchuk TJ, Linde K. A critical overview of homeopathy. Annals of Internal Medicine. 2003;138(5):393-399.

Kuehn BM. Despite health claims by manufacturers, little oversight for homeopathic products. JAMA: Journal of the 

American Medical Association. 2009;302(15):1631-1634.

Merrell WC, Shalts E. Homeopathy. Medical Clinics of North America. 2002;86(1):47-62.

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Posadzki P, Alotaibi A, Ernst E. Adverse effects of homeopathy: a systematic review of published case reports and case 

series. The International Journal of Clinical Practice. 2012;66(12):1178-1188.

Rowe T. Homeopathy. In: Goldblatt E, Snider P, Quinn S, et al., eds. Clinicians’ and Educators’ Desk Reference on the Licensed 

Complementary and Alternative Healthcare Professions. Seattle, WA: Academic Consortium for Complementary and 

Alternative Health Care; 2009.

Shang A, Huwiler-Müntener K, Nartey L, et al. Are the clinical effects of homoeopathy placebo effects? Comparative 

study of placebo-controlled trials of homoeopathy and allopathy. Lancet. 2005;366(9487):726-732.

Tedesco P, Cicchetti J. Like cures like: homeopathy. American Journal of Nursing. 2001;101(9):43-49.

U.S. Food and Drug Administration. Manual of Compliance Policy Guides. Sec. 400.400. Conditions Under Which Homeopathic 

Drugs May Be Marketed. U.S. Food and Drug Administration Web site. Accessed at http://www.fda.gov/ICECI/

ComplianceManuals/CompliancePolicyGuidanceManual/ucm074360.htm on March 22, 2012.

Vallance AK. Can biological activity be maintained at ultra-high dilution? An overview of homeopathy, evidence, and 

Bayesian philosophy. Journal of Alternative and Complementary Medicine. 1998;4(1):49-76.

For More Information

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and (in most cases) brief summaries of articles from scientific and medical journals.

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You, to help people learn about clinical trials, why they matter, and how to participate. The 

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Web site: www.nih.gov/health/clinicaltrials/

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Research Portfolio Online Reporting Tools Expenditures & Results (RePORTER)

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Web site: projectreporter.nih.gov/reporter.cfm

MedlinePlus

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National Library of Medicine) brings together authoritative information from the national 

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Acknowledgments 

NCCAM thanks the following people for their technical expertise and review of the update 

of this publication: Elisabeth Walther, Pharm.D., J.D. and colleagues, Office of Compliance, 

Center for Drug Evaluation and Research, U.S. Food and Drug Administration, and John 

(Jack) Killen, Jr., M.D., NCCAM.

This publication is not copyrighted and is in the public domain.

Duplication is encouraged.

NCCAM has provided this material for your information. It is not intended to substitute for the 

medical expertise 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.

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Created July 2009

Updated May 2013