Horse Chestnut
Aesculus hippocastanum L.
Horse Chestnut (Aesculus hippocastanum) is a large ornamental shade tree with palmate leaves, upright clusters of white flowers in spring, and glossy brown seeds encased in a spiky green husk — resembling, but botanically unrelated to, edible chestnuts.
Last reviewed August 8, 2026
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Is Horse Chestnut safe to use?
Raw horse chestnut seeds, bark, leaves, and flowers are toxic — they contain esculin, and the FDA classifies horse chestnut as an unsafe herb outside of properly processed, standardized extract. Only commercially standardized seed extract (typically 16-20% aescin), with the toxic component removed during processing, is appropriate for use, and even then only short-term. Horse chestnuts are not the same plant as edible chestnuts (Castanea species) and are never edible in any raw form. Standardized extract carries a mild blood-thinning effect — use caution with anticoagulant medications and stop at least 2 weeks before surgery. Avoid during pregnancy and in anyone with liver conditions unless supervised by a healthcare provider. Possible cross-reactivity in those with a latex or tree-nut allergy.
This is educational information, not medical advice. See our full Disclaimer before use.
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