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Research · Supplements

Horse chestnut

In chronic venous insufficiency, two meta-analyses found horse chestnut seed extract lowered leg volume by about 32 to 46 mL against placebo, and most trials found less leg pain. One trial found it matched compression stockings for swelling. Trial side effects were mild. Case reports describe liver injury and, after intravenous aescin, kidney failure.

Add to Bio HackChecked 2026-11-09
Status
Dietary supplement in the US. Not FDA-approved for any condition.
Also called
Aesculus hippocastanum, horse chestnut seed extract, HCSE, escin, aescin, beta-escin, Venostasin, Venoplant, buckeye
Taken for
chronic venous insufficiency, varicose veins, leg swelling, swelling, edema, leg pain, heavy legs, hemorrhoids

Strong several reviews agree · Moderate one review or consistent trials · Limited one or a few small studies · Untested no study in people, listed with what it rests on

Shown to help3

Reported risks2

What people take it for, and what was found

Shown to help3

Strong

Leg swelling in chronic venous insufficiency

Shown to reduce leg volume about 32 to 46 mL over placebo in adults with chronic venous insufficiency, similar to compression stockings in one trial.

The numbers and sources
Effect
In six placebo-controlled trials (502 people), leg volume fell by 32.1 mL more on horse chestnut seed extract than on placebo (95% CI 13.49 to 50.72) [1]. A separate meta-analysis of 13 RCTs (1,051 patients) found leg volume 46.4 mL lower than placebo (95% CI 11.3 to 81.4) and a 1.5-fold higher chance of improved edema (95% CI 1.2 to 1.9) [2]. In 240 patients over 12 weeks, lower leg volume fell by 43.8 mL on extract with 50 mg aescin twice a day and by 46.7 mL with class II compression stockings, and rose by 9.8 mL on placebo. Both treatments differed from placebo and were equivalent to each other [3].
Population
Adults with chronic venous insufficiency in RCTs [1][2]. 240 patients [3].
Sources
[1], [2], [3]
Caveats
The Cochrane authors call for larger trials to confirm the effect [1]. Trials lasted weeks to months. The compression trial was only partially blinded [3].
Moderate

Leg pain, itching and heaviness

Shown to reduce leg pain in most trials in adults with chronic venous insufficiency, though one pooled estimate included no difference.

The numbers and sources
Effect
Six of seven placebo-controlled trials reported less leg pain on the extract. One trial gave a difference of 42.4 mm on a 100 mm scale (95% CI 34.9 to 49.9) [1]. In the second meta-analysis, the odds of improved leg pain were 4.1 times higher (95% CI 0.98 to 16.8), an interval that includes no difference. Itching improved 1.7-fold (95% CI 0.01 to 3.0). Evidence on leg fatigue, heaviness and calf cramps was insufficient [2]. An earlier review of double-blind trials reported less leg pain, itching, fatigue and tenseness [4].
Population
Adults with chronic venous insufficiency in RCTs [1][2][4].
Sources
[1], [2], [4]
Caveats
The 1998 review and the Cochrane review share authors [1][4]. Pain was measured in different ways across trials.
Limited

Hemorrhoids

Small trials found escin added to MPFF stopped hemorrhoid bleeding sooner and cut recurrence at 3 months, 7% against 24%.

The numbers and sources
Effect
In adults with grade 1 or 2 bleeding internal hemorrhoids, adding aescin to micronized purified flavonoid fraction (MPFF) stopped bleeding in a median 2 days, against 4 days on MPFF alone [5]. Among 108 patients whose bleeding stopped, recurrence at 3 months was 7.02% with escin 120 mg a day and 23.52% with placebo, both alongside MPFF (hazard ratio 3.95, p 0.009) [6].
Population
Adults at one colorectal surgery division in Thailand. The abstract reports 120 patients randomized to each group [5]. 108 patients who reached hemostasis [6].
Sources
[5], [6]
Caveats
Both trials tested escin added to MPFF, not escin alone, and share authors [5][6].

Doses studied

The compression comparison trial used dried horse chestnut seed extract with 50 mg aescin twice a day for 12 weeks [3]. The hemorrhoid trial used escin 120 mg a day alongside MPFF 3,000 mg a day for 7 days, then MPFF 1,000 mg a day with escin for 2 months [6].

Risks

Reported risks2

Limited

Liver injury

Case reports: liver injury in a man taking a horse chestnut supplement and in a man given an injected extract.

The numbers and sources
Effect
A 70-year-old man developed idiosyncratic drug-induced liver injury attributed to a horse chestnut dietary supplement [7]. A 37-year-old man developed jaundice 60 days after a 65 mg injection of Venoplant, a horse chestnut extract. His liver biopsy showed marked cholestasis with zonal necrosis, and a lymphocyte stimulation test was positive [8]. A 46-year-old man who ate a horse chestnut seed, mistaking it for an edible chestnut, had slightly raised liver enzymes and amylase and a brief episode of atrial fibrillation, all normal the next day [9].
Population
Single case reports [7][8][9].
Sources
[7], [8], [9]
Caveats
Case reports cannot give a rate. One case followed an injection and one followed eating the raw seed, not taking the extract.
Limited

Kidney failure after intravenous aescin

Case reports: one heart surgery center linked acute kidney failure, mostly in young children, to intravenous aescin. Oral extract was not involved.

The numbers and sources
Effect
One heart surgery center linked a rise in acute kidney failure after cardiac surgery, mostly in children aged 2 to 10, to intravenous aescin. 39% of affected patients needed peritoneal dialysis and overall mortality was 10.7%. No similar case occurred in almost a year after the drug was dropped [10].
Population
Patients after heart surgery at one center [10].
Sources
[10]
Caveats
This concerns intravenous aescin, not oral extract. The abstract does not give the number of cases.

Checked, no increase found1

Moderate

Adverse events in trials

Adverse events were mild, infrequent and about as common as on placebo in short trials.

The numbers and sources
Effect
Adverse events were usually mild and infrequent across the Cochrane trials [1]. Across 13 RCTs, no severe adverse events were reported and mild adverse events did not rise significantly over placebo [2]. No serious treatment-related events were reported in the compression trial [3].
Population
Adults with chronic venous insufficiency in RCTs [1][2][3].
Sources
[1], [2], [3]
Caveats
Trials were short, so longer use was not studied.

Claims tested and not found

  1. That horse chestnut seed extract reduces leg fatigue, heaviness or calf cramps. A meta-analysis of 13 RCTs found the evidence insufficient to show an effect on these symptoms [2].

Sources

  1. Pittler MH, Ernst E. Horse chestnut seed extract for chronic venous insufficiency. Cochrane Database of Systematic Reviews. 2012. https://doi.org/10.1002/14651858.CD003230.pub4
  2. Siebert U, Brach M, Sroczynski G, Berla K. Efficacy, routine effectiveness, and safety of horsechestnut seed extract in the treatment of chronic venous insufficiency. A meta-analysis of randomized controlled trials and large observational studies. International Angiology. 2002. https://pubmed.ncbi.nlm.nih.gov/12518108/
  3. Diehm C, Trampisch HJ, Lange S, Schmidt C. Comparison of leg compression stocking and oral horse-chestnut seed extract therapy in patients with chronic venous insufficiency. The Lancet. 1996. https://doi.org/10.1016/s0140-6736(96)90467-5
  4. Pittler MH, Ernst E. Horse-chestnut seed extract for chronic venous insufficiency. A criteria-based systematic review. Archives of Dermatology. 1998. https://doi.org/10.1001/archderm.134.11.1356
  5. Sanmee S, Vipudhamorn W, Sutharat P, Supatrakul E. The efficacy of Aescin combined with MPFF for early control of bleeding from acute hemorrhoids, A randomized controlled trial. Asian Journal of Surgery. 2025. https://doi.org/10.1016/j.asjsur.2024.07.336
  6. Vipudhamorn W, Sutharat P, Sanmee S, et al. Efficacy of escin combined with micronized purified flavonoid fraction in controlling bleeding and preventing recurrence of acute internal hemorrhoids: a randomized controlled trial. Annals of Coloproctology. 2026. https://doi.org/10.3393/ac.2025.01207.0172
  7. Costa Santos D, Lérias G, Madruga I. Drug-induced Liver Injury Due to a Horse Chestnut Dietary Supplement. European Journal of Case Reports in Internal Medicine. 2021. https://doi.org/10.12890/2021_002389
  8. Takegoshi K, Tohyama T, Okuda K, et al. A case of Venoplant-induced hepatic injury. Gastroenterologia Japonica. 1986. https://doi.org/10.1007/BF02775942
  9. Yi HY, Lee JY. Poisoning due to consumption of horse chestnut seed. Clinical and Experimental Emergency Medicine. 2021. https://doi.org/10.15441/ceem.20.004
  10. Hellberg K, Ruschewski W, de Vivie R. Medikamentös bedingtes post-operatives Nierenversagen nach herzchirurgischen Eingriffen. The Thoracic and Cardiovascular Surgeon. 1975. https://doi.org/10.1055/s-0028-1096991

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