Horse Chestnut

Horse Chestnut

Common Names

  • Chestnut
  • Marron europeen
  • Escine
  • Escin
  • Aescin

For Patients & Caregivers

Tell your healthcare providers about any dietary supplements you’re taking, such as herbs, vitamins, minerals, and natural or home remedies. This will help them manage your care and keep you safe.

How It Works

Horse chestnut was shown to be effective for treating chronic venous insufficiency but its long-term effects are not known.

Horse chestnut is a seed extract. One of its active components is aescin, which may reduce inflammation and increase the tone of veins. It also reduces the release of enzymes, which is typically increased in chronic diseases of the vein. Other compounds in horse chestnut generally increase the tone of blood vessels and decrease their permeability. Horse chestnut extract was shown in some studies to be effective against chronic venous insufficiency.

A compound called aesculetin may act as an anticoagulant and blood thinner, and is therefore often excluded from over-the-counter horse chestnut products.

Purported Uses
  • To treat circulatory disorders
    Several clinical trials support use of horse chestnut as a short-term treatment for CVI, but its long-term effects are unknown.
  • To treat phlebitis
    No scientific evidence supports this use.
  • To treat varicose veins
    This claim is not backed by any evidence.
  • To treat diarrhea
    There is no scientific evidence to back this claim.
  • To treat hemorrhoids
    There are no data to support this.
Patient Warnings
  • Horse chestnut seed is classified by the FDA as an unsafe herb. Many of the compounds in horse chestnut are considered to be toxic.
Do Not Take If
  • You are taking warfarin, aspirin, or other blood thinners: Horse chestnut products that contain aesculin may increase the risk of bleeding. Check to make sure that your horse chestnut product is aesculin-free.
  • You are taking drugs that are substrates of Cytochrome P450 enzymes: Horse chestnut may increase the side effects, and may also reduce the effectiveness of such drugs.
Side Effects

Chestnut poisoning: Diarrhea, muscle twitching, dilated pupils, depression, and paralysis can occur after high doses of horse chestnut.

Case Reports

  • Intestinal obstructions: Several cases requiring surgery for removal have occurred with the excessive consumption of horse chestnuts.
  • Life-threatening kidney rupture: In a patient with a benign kidney tumor, after taking horse chestnut seed extract for venous insufficiency. 
  • Inflammation around the heart and shortness of breath: In a 32-year-old man who had consumed 3 boxes of horse chestnut paste over 6 weeks.
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For Healthcare Professionals

Brand Name
Scientific Name
Aesculus hippocastanum
Clinical Summary

Horse chestnut, a tree native to the Balkan Peninsula, has been used in traditional medicine for centuries. The seed extract is used as a dietary supplement to support vascular function. Horse chestnut should not be confused with sweet chestnut.

Laboratory studies suggest that the compound in horse chestnut known as aescin, or escin, has anti-inflammatory (1), neuroprotective (1), and antitumor (2) (3) effects, and enhances the efficacy of gemcitabine (18).

Data from earlier clinical trials suggest efficacy of horse chestnut seed extract against chronic venous insufficiency (CVI) (4) (5). Although systematic reviews and meta analysis state that horse chestnut extract is a safe and well tolerated treatment for CVI (6) (7) (8), a Cochrane review of rutosides did not find any clear evidence of benefit for post-thrombotic syndrome (11).

Other studies suggest escin may be effective in improving sperm quality in patients with varicocele-associated infertility (14).

Patients with compromised renal or hepatic function should not consume horse chestnut products.

Purported Uses
  • Circulatory disorders
  • Phlebitis
  • Varicose veins
  • Diarrhea
  • Hemorrhoids
Mechanism of Action

Escin, also known as Aescin, a natural mixture of triterpenoid saponins isolated from the seed of the horse chestnut has been identified as the active principle. The anti-inflammatory effects of escin involve significant downregulation of expression of certain inflammatory genes, and upregulation of expression of granulocyte-macrophage colony-stimulating factor (GM-CSF), which also confers neuroprotection (1).

One of the mechanisms by which escin reduces chronic venous insufficiency is thought to be via inhibition of elastase and hyaluronidase, both involved in enzymatic proteoglycan degradation, which constitutes part of the capillary endothelium and is also the main component of the extravascular matrix (19). The contraction of veins and arteries by horse chestnut is believed, to be partially mediated through 5-HT(2A) receptors; horse chestnut also reduced platelet aggregation in vitro (20).

Beta-aescin and 5-fluorouracil were reported to inhibit human hepatocellular carcinoma SMMC-7721 cells, which may be due to the synergistic effects including cell-cycle arrest, induction of apoptosis, activation of caspases-3, 8 and 9, and down-regulation of Bcl-2 expression (17). In another study, escin was shown to potentiate the efficacy of gemcitabine, partially due to the inhibition of the nuclear transcription factor (NF-κB) activity and consequent inhibition of c-Myc, COX-2, Cyclin D1, Survivin, Bcl-2 and Bcl-xL, and the activation of caspase-3 (18).


Horse chestnut seeds are classified by the FDA as unsafe because of their toxic effects which include depression, muscular incoordination, paralysis, coma, and death (21).

Adverse Reactions

Chestnut poisoning: Diarrhea, muscle twitching, dilated pupils, depression, and paralysis (14).

Case Reports

Intestinal obstruction: Caused by excessive consumption of horse chestnuts. In cases with bezoars surgical removal was required (15) (12) (13).
Life-threatening kidney rupture: In a patient with angiomyolipoma, a benign fat-containing mesenchymal tumor of the kidney, after taking horse chestnut seed extract for venous insufficiency. Symptoms improved after an emergency embolization (16).
Pericarditis and dyspnea: In a 32-year-old man who had consumed 3 boxes of horse chestnut paste over 6 weeks  (14).

Herb-Drug Interactions
  • Anticoagulants / Antiplatelet agents: Horse chestnut may have an additive anticoagulant effect due to aesculin, a hydroxycoumarin (9).
  • Cytochrome P450 substrates: Aescin was shown to both inhibit and induce CYP1A2, CYP2C9 and CYP3A4 enzymes in a study of rats, and may affect the intracellular concentration of drugs metabolized by these enzymes (22). Clinical relevance has yet to be determined.
Dosage (OneMSK Only)
  1. Zhang L, Fu F, Zhang X et al. Escin attenuates cognitive deficits and hippocampal injury after transient global cerebral ischemia in mice via regulating certain inflammatory genes. Neurochem Int. 2010 Sep;57(2):119-27.
  2. Zhou XY, Fu FH, Li Z, et al. Escin, a natural mixture of triterpene saponins, exhibits antitumor activity against hepatocellular carcinoma. Planta Med. 2009 Dec;75(15):1580-5.
  3. Harikumar KB, Sung B, Pandey MK, et al. Escin, a pentacyclic triterpene, chemosensitizes human tumor cells through inhibition of nuclear factor-kappaB signaling pathway. Mol Pharmacol. 2010 May;77(5):818-27.
  4. 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. Lancet. 1996;347:292-4.
  5. Diehm C, Vollbrecht D, Amendt K, Comberg HU. Medical edema protection—clinical benefit in patients with chronic deep vein incompetence. A placebo controlled double blind study. Vasa. 1992;21:188-92.
  6. 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. Int Angiol. 2002 Dec;21(4):305-15.
  7. Pittler MH, et al.Horse-chestnut seed extract for chronic venous insufficiency. A criteria-based systematic review. Arch Dermatol. 1998;134:1356-60.
  8. Pittler MH, Ernst E. Horse chestnut seed extract for chronic venous insufficiency. Cochrane Database Syst Rev. 2006 Jan 25;(1):CD003230. 
  9. Heck AM, DeWitt BA, Lukes AL. Potential interactions between alternative therapies and warfarin. Am J Health Syst Pharm. Jul 1 2000;57(13):1221-1227; quiz 1228-1230.
  10. Morling JR, Broderick C, Yeoh SE, et al. Rutosides for treatment of post-thrombotic syndrome. Cochrane Database Syst Rev. Nov 8 2018;11:Cd005625.
  11. Satake R, Chinda D, Shimoyama T, et al. Repeated Small Bowel Obstruction Caused by Chestnut Ingestion without the Formation of Phytobezoars. Intern Med. 2016;55(12):1565-1568.
  12. Ravindra RK, Das A, Chew GL, et al. Small bowel obstruction with multiple perforations post chestnut ingestion. BMJ Case Rep. Feb 3 2019;12(2).
  13. Edem E, Kahyaoglu B, Cakar MA. Acute Effusive Pericarditis due to Horse Chestnut Consumption. Am J Case Rep. May 4 2016;17:305-308.
  14. Fang Y, Zhao L, Yan F, et al. Escin improves sperm quality in male patients with varicocele-associated infertility. Phytomedicine. 2010 Mar;17(3-4):192-6.
  15. Chen WT, Suk FM. Abdominal pain after consuming a chestnut. Diagnosis: Chestnut bezoar in the jejunum. Gastroenterology. 2011 Jun;140(7):e9-10.
  16. Snow A, Halpenny D, Mc Neill G, Torreggiani WC. Life-threatening rupture of a renal angiomyolipoma in a patient taking over-the-counter horse chestnut seed extract. J Emerg Med. 2012 Dec;43(6):e401-3.
  17. Ming ZJ, Hu Y, Qiu YH, Cao L, Zhang XG. Synergistic effects of beta-aescin and 5-fluorouracil in human hepatocellular carcinoma SMMC-7721 cells.Phytomedicine. 2010;17(8-9):575-80.
  18. Wang YW, Wang SJ, Zhou YN, Pan SH, Sun B. Escin augments the efficacy of gemcitabine through down-regulation of nuclear factor-κB and nuclear factor-κB-regulated gene products in pancreatic cancer both in vitro and in vivo. J Cancer Res Clin Oncol. 2012 May;138(5):785-97.
  19. Facino RM, Carini M, Stefani R, Aldini G, Saibene L.  Anti-elastase and anti-hyaluronidase activities of saponins and sapogenins from Hedera helix, Aesculus hippocastanum, and Ruscus aculeatus: factors contributing to their efficacy in the treatment of venous insufficiency. Arch Pharm (Weinheim). 1995;328720-724.
  20. Felixsson E, Persson IA, Eriksson AC, Persson K. Horse chestnut extract contracts bovine vessels and affects human platelet aggregation through 5-HT(2A) receptors: an in vitro study. Phytother Res. 2010 Sep;24(9):1297-301.
  21. FDA Poisonous Plant Database. Accessed February 13, 2020.
  22. Huang Y, Zheng SL, Zhu HY, Xu ZS, Xu RA. Effects of aescin on cytochrome P450 enzymes in rats. J Ethnopharmacol. 2014;151(1):583-90.
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