Horse chestnut

Why horse chestnut treatment is not in vein

The Irish Times
Health Supplement, p. 13
May 2008


DOES IT WORK?: Horse chestnut extract has been used to treat varicose veins with a fair degree of success, writes Dónal O’Mathúna.

THE HORSE chestnut is the most common chestnut tree found in Ireland. The nuts falling at this time of the year can be as good as conkers, but they shouldn’t be eaten. “Chestnuts roasting on an open fire,” conjures up romantic Christmas scenes, but edible chestnuts come from chestnut species that are rarely found in Ireland. However, an extract made from the type of chestnuts that do grow here has a long traditional use. Recent research is providing evidence that it can help some people with varicose veins.

Varicose veins are a common and painful condition afflicting 20-25 per cent of women and 10-15 per cent of men. The condition most obviously affects the legs. Blood travels back to the heart via the veins. Valves prevent the blood falling back down the legs. If these valves become damaged or leak, the blood pools in the leg’s vein.

When this happens in veins close to the skin, the typical blue, bulging and twisted varicose veins develop. When the veins deeper inside the legs are affected, the condition is called chronic venous insufficiency (CVI). This leads to swelling, pain and hardening of the skin, which can lead to more serious problems with blood clots and ulcers.

Compression stockings are the main approach to treatment, although varicose veins can be surgically removed. Avoiding long periods of sitting and getting exercise help prevent the condition, but once it develops, the legs are often painful, weak and tired, making movement more difficult.

Evidence from studies

Several laboratory and animal studies have found that the active ingredient in chestnut is a compound called aescin. In experiments, aescin caused veins to contract better and with more force. Water and other materials were less able to pass through the walls of blood vessels, which is the underlying problem with varicose veins.

A systematic review of horse chestnut capsules has been published in the Cochrane Library. This independent, international organisation reviews various types of treatment and is available without charge when accessing the internet within Ireland ( This review found 17 controlled trials of horse chestnut for CVI. The trials used different symptoms to evaluate the extract. Most trials found horse chestnut more beneficial than placebo.

For example, horse chestnut relieved pain better than placebo in six of the seven trials. In four of six trials measuring leg swelling, horse chestnut was significantly better. Four of eight trials found horse chestnut reduced itching. Two studies compared horse chestnut extract to compression stockings, and found them equally effective in relieving leg pain.

Problematic aspects

Research studies have found few adverse effects from high-quality chestnut extracts. Some people reported dizziness, nausea or headache, but those effects lasted a short time. Remember that horse chestnuts themselves are poisonous, as are the leaves, flowers and older bark of the tree. Chestnuts contain a poison called aesculin, which is chemically similar to warfarin and causes prolonged bleeding. Good-quality products should state that aesculin is not present. Extracts should be standardised to state how much active ingredient (aescin) each dose contains.


Horse chestnut seed extract has consistently shown benefit for the short-term treatment of varicose veins. Since treatment for this condition will need to continue for many years, long-term studies are needed.

The extract has been safe in short-term studies. The usual dose has been 300-600mg of extract, which is usually standardised to give 50-100mg aescin.

Given the lack of other satisfactory treatments for varicose veins, horse chestnut seed extract may be a helpful alternative to compression stockings. Hwever, anyone using blood-thinning medications should be certain the product contains no aesculin.
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