Oral horse chestnut seed extract is likely effective in reducing symptoms of chronic venous insufficiency, which can include varicose veins, itching, swelling in the legs, pain in the legs and fluid retention, states Everyday Health. Conversely, raw horse chestnut seeds, leaves, bark and flowers are highly poisonous and may cause death.
Horse chestnut, or aesculus hippocastanum, is an alternative medicine that traditional doctors have used for centuries as a tonic and to treat arthritis, gynecological bleeding and rheumatism, explains Drugs.com. However, because of the high level of toxicity in all its plant parts, the U.S. Food and Drug Administration has classified the horse chestnut as an unsafe herb.
Since the horse chestnut does not have approval from the FDA for medicinal use, patients should not use it as a substitute for medicine prescribed by their doctors, cautions Everyday Health. Though the seed extract is available as an herbal supplement, it does not pass through any regulations of manufacturing standards.
Even as a supplement, horse chestnut is probably safe for use for a short period only and may result in poisoning if used without care, adds Everyday Health. Signs of horse chestnut poisoning need immediate medical attention and include twitching muscles, loss of coordination, diarrhea, weakness and vomiting.