An herb with the unlikely name of horse chestnut may prove to hold some of the keys to managing chronic venous insufficiency (CVI). Approximately 10%-15% of men and 20%-25% of women are afflicted by this condition, which causes leg heaviness, aching, varicose veins, significant edema, and, in more severe cases, chronic ulcerations, skin changes, and infection.


Horse chestnut (Aesculus hippocastanum) is also known as buckeye and Spanish chestnut (not to be confused with the edible chestnut). Although the tall, treelike plant is mainly grown as an ornamental, its medicinal properties have been touted for centuries. Dioscorides, known as the father of herbal medicine, first detailed the remedy in Materia Medica in 1566.

The leaves of the tree have been used historically to treat cough and fever and relieve the pain and inflammation of arthritis. Topical preparations are used in Europe for treating sprains. And the seed extract has also been used to alleviate lower-extremity edema and the discomfort caused by hemorrhoids.1 However, there are no studies confirming the herb’s effectiveness for these ailments. The only condition for which supportive scientific evidence exists is CVI.

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Mechanism of action

The active ingredient of horse chestnut seed extract (HCSE) is escin, a complex mix of more than 30 triterpenic saponin glycosides.2 Escin is believed to have enzymatic properties that inhibit leukocyte activation. Decreased leukocyte activation, together with cholesterol-containing lysosomal membrane stabilization, inhibits the release of elastase and hyaluronidase, both of which worsen inflammatory changes of CVI.3 By decreasing this inflammatory action and reducing the basis for worsening edema, HCSE decreases the overall volume of the limb. With elimination of the potentiating factor of inflammation, the circular dilemma of inflammation, capillary fragility, transcapillary water and protein filtration, and worsening volume-related pressure is negated. Some evidence also suggests that HCSE has a venous tone-enhancing property through the effect of noradrenaline and prostaglandin F2a.3

Scientific data

A meta-analysis of 14 double-blinded, randomized, controlled trials examined the use of A. hippocastanum in more than 5,000 patients.4 Improved standardized measurements of lower-leg circumference at the calf and ankle were statistically significant in all trials. Leg pain, pruritus, and fatigue were also reduced in those taking HCSE. In the trial with the best measurement methodology, HCSE exceeded traditional therapy of compression stockings for lower-leg edema after 12 weeks of use.4

A recent Cochrane review of seven placebo-controlled trials assessed the efficacy of HCSE vs. placebo.5 In six of the trials, significant pain reduction was reported in those taking HCSE vs. placebo. The seventh trial reported statistically significant improvement in pain compared with baseline.


Allergic skin reactions have been reported with the use of topical creams containing HCSE. Patients with pollen-based allergies should also use caution when taking HCSE. IV injections of the extract may cause serious reactions, including anaphylactic shock.

No safety data are available for women who are nursing, pregnant, or trying to become pregnant, so the herb should not be used by this population. No scientific data exist regarding the effects of HCSE in children. However, because CVI is not typically a disease of young persons, this is of little concern. HCSE should not be used concomitantly with anticoagulants, including warfarin (Coumadin), heparin, and aspirin, because the herb has a tendency to potentiate the anticoagulant action and can be hazardous.1 Patients on anticoagulation who wish to take the supplement should do so only under medical supervision.

Side effects

In the aforementioned meta-analysis of 5,000 patients, the side effect incidence was 0.6%.4 Pruritus, nausea and other GI effects, headache, calf cramping, and dizziness were the most commonly listed problems.4 Patients using HCSE should be monitored for liver function abnormalities on a routine basis.


Ripe, dried seeds are commercially processed so the toxic components can be extracted and the purified escin isolated. It is important to note that unprocessed seeds (as well as leaves, bark, and flowers) contain esculin, which is poisonous.6 Novice herb gardeners should under no circumstances attempt to grow and produce HCSE for personal use. Only commercial, properly processed and extracted product should be used.


HCSE is most commonly available as capsules, although it can also be found in tablet and tincture form. Capsules with dosage standardized to 16%-20% escin should be used at 300 mg orally twice daily.1


While further testing continues, specifically by the National Center for Complementary and Alternative Medicine, sufficient data exist to add oral HCSE to the treatment arsenal for CVI. Although cited studies used HCSE as monotherapy for study purposes, patients with significant disease should be advised to combine the extract with traditional disease-management components of diuresis, weight loss, and compression in order to maximize the efficacy of their treatment.

Ms. Sego is a staff clinician at the Veterans Administration Hospital in Kansas City, Mo., where she practices adult medicine and women’s health. She also teaches at the nursing schools of the University of Missouri and the University of Kansas.


1. National Center for Complementary and Alternative Medicine. Horse Chestnut. Available at Accessed November 9, 2006.

2. Pittler MH, Ernst E. Horse-chestnut seed extract for chronic venous insufficiency. Arch Dermatol. 1998;134:1356-1360.

3. Horse Chestnut (Aesculus hippocastanum). Available at Accessed November 9, 2006.

4. Diehm C, Trampisch HJ, Lange S, Schmidt C. Comparison of leg compression stockings and oral horse chestnut seed extract therapy in patients with chronic venous insufficiency. Lancet. 1996;347:292-294.

5. Pittler MH, Ernst E. Horse chestnut seed extract for chronic venous insufficiency. Cochrane Database Syst Rev. 2006;(1):CD003230.

6. Alquire PA, Mathes BM. Patient information: Chronic venous insufficiency. Available at Accessed November 9, 2006.