What is Horse Chestnut?

The horse chestnut tree is widely cultivated for its bright white, yellow, or red flower clusters. Closely related to the Ohio buckeye, this tree produces large seeds known as horse chestnuts. A superstition in many parts of Europe suggests that carrying these seeds in your pocket will ward off rheumatism. More serious medical uses date back to nineteenth-century France, where extracts were used to treat hemorrhoids.

Serious German research of this herb began in the 1960s and ultimately led to the approval of a horse chestnut extract for vein diseases of the legs. Horse chestnut is the third most common single-herb product sold in Germany, after ginkgo and St. John's wort . In Japan, an injectable form of horse chestnut is widely used to reduce inflammation after surgery or injury; however, it is not available in the United States, and it may present safety risks.

The active ingredients in horse chestnut appear to be a group of chemicals called saponins, of which aescin is considered the most important. Aescin appears to reduce swelling and inflammation. ¹ It's not exactly clear how aescin might work, but theories include "sealing" leaking capillaries, improving the elastic strength of...

Safety Issues

Whole horse chestnut is classified as an unsafe herb by the FDA. Eating the nuts or drinking a tea made from the leaves can cause horse chestnut poisoning, the symptoms of which include nausea, vomiting, diarrhea, salivation, headache, breakdown of red blood cells, convulsions, and circulatory and respiratory failure possibly leading to death. ² However, manufacturers of the typical European standardized extract formulations remove the most toxic constituent (esculin) and standardize the quantity of aescin. To prevent stomach irritation caused by another ingredient of horse chestnut, the extract is supplied in a controlled-release product, which reduces the incidence of irritation to below 1%, even at higher doses. ³ Properly prepared horse chestnut products...