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Horse Chestnut

Low Risk

Also known as:

Buckeye Marronnier

A close up image of the flowers, leaves, seed pods, and seeds of the horse chestnut tree on a white background.
Possible Symptoms
  • Abdominal cramping
  • Nausea and vomiting
  • Diarrhea
  • Muscle aches
  • Headache
What to Do
  1. Wipe or rinse out mouth.
  2. Give a serving size of water to drink.
  3. Call 1-800-222-1222 for additional instructions.

Additional Information

Quick Facts about horse chestnut:

The horse chestnut tree (Aesculus hippocastanum) is a large tree that is also known by the names Buckeye and Marronnier. “Natural medicine” practices use the seeds, leaves, bark, and flowers to relieve circulation problems, hemorrhoids, and varicose veins. As with all supplements, horse chestnut is not FDA approved for any disease state. The FDA does not regulate supplements, so the content of products may differ from what the label says it has. Talk with your healthcare provider before using the supplement.

Risk of esculin

If someone swallows any part of the tree in its unprocessed or natural form, there is a chance of becoming sick because it contains a poisonous substance called esculin. This substance can irritate the stomach and increase the risk of bleeding. Proper processing removes the toxin esculin and makes it safer to ingest. But even after processing, horse chestnut can still cause side effects such as gastrointestinal irritation, nausea, diarrhea, itching, muscle aches, and headache. People with a history of kidney disease, liver disease, or bleeding disorders should not use horse chestnut in any form, including raw extracts and supplements. Also, those who take blood-thinning or antiplatelet medications such as aspirin, Coumadin® (warfarin), or Plavix® (clopidogrel) should not take this supplement.

Horse chestnut vs chestnuts

In addition to questions about supplements, sometimes we receive calls because someone mistakes the horse chestnut (Aesculus) for the edible chestnut (Castanea). The two trees are similar in appearance, while there are noticeable differences in the seed pods. The edible chestnut pod has a very spiny covering that looks furry. In contrast, the horse chestnut’s seed pods have widely spaced burrs and are completely round with a leathery outside. Edible chestnuts contain multiple nuts inside, while the horse chestnut contains 1 or 2 seeds. These seeds have a pale spot on the nut – giving it the common name “buckeye.” Lastly, the edible chestnut has a very starchy taste, and the horse chestnut has a bitter and unpleasant taste.

What to do if there is an exposure

If you find someone has eaten any part of the horse chestnut tree or had a medicine mishap with the supplement, do not panic. Wipe out the mouth with a soft, wet cloth and give them some water to drink. If problems start or you have questions, call the Missouri Poison Center right away at 1-800-222-1222. The poison center is open all day, every day, for poisoning emergencies and questions.

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