Horse Chestnut

© Steven Foster

This fact sheet provides basic information about horse chestnut—

common names, what the science says, potential side effects and 

cautions, and resources for more information.

Common Names—horse chestnut, buckeye, Spanish chestnut

Latin Name—Aesculus hippocastanum

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.

For centuries, horse chestnut seeds, leaves, bark, and flowers were used 

for a variety of conditions and diseases. Today, horse chestnut seed 

extract is used primarily as a folk or traditional remedy for 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. The seed extract has also been used as a 

folk or traditional remedy for hemorrhoids.

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 

• 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.

• 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 

• Do not use raw or unprocessed horse chestnut seeds, leaves, bark, or flowers. They contain 

esculin, which is poisonous.

• 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.

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

them a full picture of what you do to manage your health. This will help ensure 

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

complementary and alternative medicine, see NCCAM’s Time to Talk campaign at 

nccam.nih.gov/timetotalk/. 

Sources

Horse chestnut. Natural Medicines Comprehensive Database Web site. Accessed at www.naturaldatabase.com on 

September 8, 2009.

Horse chestnut. Natural Standard Database Web site. Accessed at www.naturalstandard.com on September 8, 2009.

Horse chestnut seed extract. In: Blumenthal M, Goldberg A, Brinckman J, eds. Herbal Medicine: Expanded Commission E 

Monographs. Newton, MA: Lippincott Williams & Wilkins; 2000:201-204.

For More Information

Visit the NCCAM Web site at nccam.nih.gov and view Using Dietary Supplements Wisely

(nccam.nih.gov/health/supplements/wiseuse.htm).

NCCAM Clearinghouse

Toll-free in the U.S.: 1-888-644-6226

TTY (for deaf and hard-of-hearing callers): 1-866-464-3615

E-mail: info@nccam.nih.gov

PubMed®

Web site: www.ncbi.nlm.nih.gov/sites/entrez

NIH Office of Dietary Supplements

Web site: www.ods.od.nih.gov

NIH National Library of Medicine’s MedlinePlus

Horse Chestnut Listing: www.nlm.nih.gov/medlineplus/druginfo/natural/1055.html

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.

National Institutes of Health

♦♦♦

U.S. Department of Health and Human Services

D321

Created May 2006

Updated April 2012