Herbs & Botanicals · Herbs · Seed extract for leg veins, with moderate evidence and a clear warning about raw seeds, bark and leaves

Horse Chestnut

Q: Does horse chestnut work for varicose veins and swollen legs?

It probably helps symptoms of chronic venous insufficiency a little, with moderate certainty. Pooled trials found less leg swelling and pain than placebo. It does not remove varicose veins. Trials were mostly small and short, and the effect is modest.

Q: Is horse chestnut as good as compression stockings?

One large 12-week trial found a similar drop in swelling. That is one trial, and a later report found stockings worked better than the extract in advanced disease. Do not stop prescribed stockings without talking to your doctor.

Q: Is it safe to eat or drink raw conkers, bark or leaves?

No. NCCIH says raw seeds, bark, flowers and leaves are unsafe by mouth because they contain a toxic component. Only standardised seed extract has been studied. One teenager became unwell after snuffing powdered seeds.

Q: What is esculin and why does it matter?

Esculin is a coumarin-type compound found in the plant, with high levels in the bark. Raw plant parts are toxic and standardised extracts have the toxic component removed (NCCIH). The NCCIH page does not name that component, so we cannot say esculin is the cause. A skin reaction to an esculin extract has been reported.

Q: Can horse chestnut harm the kidneys or liver?

Rarely, as far as is known. The EU monograph says to consult a doctor if you have kidney insufficiency. LiverTox reports rare liver injury, and one 2021 case report exists. Injectable sodium aescinate from related seeds has been linked to kidney injury in lab studies. Frequency is not known.

Q: Does it interact with blood thinners?

It might. A 2000 review lists it with herbs said to strengthen warfarin, but gives no case data, and the EU monograph reports no interactions. Tell your doctor or pharmacist before combining it, and before surgery.

Q: Can I use horse chestnut with diabetes medicines?

No human data exist. Animal work found blood-sugar lowering with some seed saponins. Check your blood sugar and ask your doctor or pharmacist.

Q: Is it safe in pregnancy or breastfeeding, or for children?

It is not recommended. The EU says safety has not been established in pregnancy or breastfeeding, and use under 18 is not recommended.

Q: What are the side effects?

Stomach upset, dizziness, headache and itching are the usual ones, and allergic reactions are possible. The Cochrane review said adverse events were usually mild and infrequent. Frequencies are not known.

Q: Does it help hemorrhoids?

Possibly. Two trials from one Thai research team found that adding escin to a flavonoid medicine stopped bleeding sooner and reduced recurrence. Escin was not tested alone, and rectal bleeding should be checked by a doctor.

Aesculus hippocastanum L. · also called European horse chestnut, conker tree, castaño de Indias (Spanish), marronnier d'Inde (French), Rosskastanie (German)

Horse chestnut is a large tree in the soapberry family. A standardised extract of its seed, rich in escin (also called aescin), is used for weak leg veins (chronic venous insufficiency). The raw seeds, bark, leaves and flowers are poisonous by mouth. Do not treat sudden leg swelling or ulcers on your own.

General information, not medical advice. Last substantive update October 25, 2026 · Not medically reviewed. A named clinician has not signed off on this page. How this page is made

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About Horse Chestnut

Horse chestnut (Aesculus hippocastanum) is a tree whose standardised seed extract is used for weak leg veins. Trials suggest a modest short-term benefit for swelling and pain in chronic venous insufficiency. The key safety message: raw seeds, bark, leaves and flowers are unsafe by mouth, and sudden leg swelling needs a doctor.

What it is

Horse chestnut is a large tree in the soapberry family (Sapindaceae), native to parts of southeastern Europe. Its seeds, called conkers, look like sweet chestnuts but are bitter and not edible.

The medicine is a standardised extract of the seed. It is adjusted to a set amount of escin-type saponins. Raw bark, leaf and flower are not used in this way.

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What makes it distinctive

It is one of the few herbs with a Cochrane review for a vein condition. The EU lists the standardised seed extract as a well-established use for chronic venous insufficiency.

Its main active group, escin, tightens veins and reduces leaking in lab and animal studies. In people the exact way it works is not known. It also contains esculin, a coumarin compound, which is why raw plant parts and extracts must be kept apart.

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Historical and current uses

Traditionally the seed was used for arthritis, pain and swelling, menstrual cramps and hemorrhoids (NCCIH). Today it is promoted mostly for leg veins.

The EU skin-use monograph is based on long use, not trials, and covers heavy legs and bruises.

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Raw plant versus standardised extract

NCCIH says raw seeds, bark, flowers and leaves are unsafe by mouth because they contain a toxic component, and that standardised seed extracts have it removed. Do not make teas or powders from conkers, bark or leaves.

The safety information for the extract applies only to short-term use (studied up to about 12 weeks). Kidney, liver, bleeding and allergy cautions are in the Safety tab.

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At a glance

Traditional uses history, not proof

Seed extract used for arthritis, pain and swelling, menstrual cramps and hemorrhoids (NCCIH)
EU well-established use of standardised dry seed extract for chronic venous insufficiency
EU traditional use of skin preparations for heavy legs and bruises

Studied for research

Chronic venous insufficiency (leg swelling, pain, itching), moderate certainty
Hemorrhoids and bruises from sports injuries, low certainty (add-on or combination products)
Post-surgery swelling, male fertility with varicocele, and others, very low certainty

Main compounds

Escin (aescin), a mix of triterpene saponins, the main active group in the seed
Esculin (aesculin), a coumarin glycoside, high in bark
Flavonoids such as quercetin and kaempferol glycosides

Common forms

Standardised dry seed extract taken by mouth (the form studied in most trials)
Gels and creams with escin, some combined with a salicylate and heparin
Not for use: raw seeds, bark, leaf or flower by mouth

Research links: NIH NCCIH: Horse Chestnut, Usefulness and Safety · EU herbal monograph on Aesculus hippocastanum seed (EMA, 2020) · Cochrane review: horse chestnut seed extract for chronic venous insufficiency (2012) · Research Library · Genes & Biomarkers Library

The plant and its history

Accepted scientific name: Aesculus hippocastanum L. (horse chestnut)
Naming authority: L., published in Sp. Pl. 344 (1753) (GBIF)
Synonyms: GBIF lists this as the accepted name; synonym list not reviewed here.
Common names: Horse chestnut (English); European horse chestnut (English); Common horse chestnut (English); Conker tree (English); Buckeye (also used for related American species) (English); Spanish chestnut (as listed by NCCIH) (English); Castaño de Indias (Spanish); Castaño de la India (Spanish); Marronnier d'Inde (French); Rosskastanie (German); Ippocastano (Italian); Castanheiro-da-Índia (Portuguese)
Botanical family: Sapindaceae (soapberry family, order Sapindales). Older books place horse chestnut in a separate family, Hippocastanaceae; GBIF now places it in Sapindaceae.
Classification: Plantae > Tracheophyta > Magnoliopsida > Sapindales > Sapindaceae > Aesculus > Aesculus hippocastanum
Native range: NCCIH: a tree native to parts of southeastern Europe. Fuller range not verified.
Habitat: Not verified in a source read for this file.
What the plant looks like: Roots: Not verified in a source read for this file.; Stems: A large tree (details not verified from a source read).; Leaves: Not verified in a source read for this file. Leaf extracts are not part of the standardised medicinal use; NCCIH says leaves are unsafe by mouth in raw form.; Flowers: Not verified in a source read for this file. NCCIH lists flowers among the unsafe raw parts.; Fruit: The fruit holds seeds ("conkers") that resemble sweet chestnuts but taste bitter (NCCIH). The seed is the part used for standardised extracts (EU monograph).
Cultivation: Not verified in a source read for this file.
Harvest and processing: Medicinal extracts are made from seed; the EU monograph lists dry extracts made with ethanol 40 to 80%, standardised to 6.5 to 10% triterpene glycosides calculated as protoaescigenin, and other extracts for traditional use (ethanol, methanol and water extracts). Harvest practices not verified.
Look-alikes and adulterants: Name: Sweet chestnut (Castanea sativa); Note: Edible nuts that resemble horse chestnut seeds; NCCIH notes the resemblance but horse chestnut seeds are bitter and unsafe raw. A sweet chestnut image in the site library is not used here.; Name: Other Aesculus species (for example Aesculus chinensis, A. wilsonii, American buckeyes); Note: Chemically similar in some cases (A. chinensis is similar to European horse chestnut) but not identical; sodium aescinate used clinically in China comes from A. wilsonii seeds.
Sustainability and conservation: Not verified. No IUCN assessment was retrieved.

Traditional use and history history, not clinical proof

Tradition or era	Documented use	Source
Traditional use (as listed by NCCIH)	Seed extract was used for arthritis, pain and swelling, menstrual cramps, hemorrhoids and other conditions; today promoted for chronic venous insufficiency, irritable bowel syndrome and male infertility.	s-nccih-horse-chestnut
European Union, well-established medicinal use	Standardised dry seed extracts, in modified or immediate-release oral forms, for the treatment of chronic venous insufficiency (swollen legs, varicose veins, heaviness, pain, tiredness, itching, tension and cramps in the calves). The monograph was first adopted 16 July 2009 and revised 15 January 2020.	s-ema-hmpc-hippocastani-semen
European Union, traditional use	Cutaneous (skin) preparations for relief of discomfort and heaviness of legs related to minor venous circulatory disturbances, and for relief of signs of bruises such as local edema and haematoma, based on long-standing use rather than trials.	s-ema-hmpc-hippocastani-semen
Other regulators and older sources	German Commission E, WHO monographs and older herbals were not read.	NOT verified

Traditional use shows how a plant was used. It does not show that a supplement works or is safe today.

What is inside, and how it may work

What the plant contains and how those compounds act in cells and animals. Laboratory and animal mechanisms are not proven effects in people.

Main compounds

Compound	Family	Where it is concentrated	Activity studied	Level of evidence
Escin / aescin (mixture of triterpene saponins; isomers escin Ia, Ib, isoescin Ia, Ib) PubChem 6433489	triterpene saponins	Seed EU monograph: extracts standardised to 6.5 to 10% triterpene glycosides as protoaescigenin (older labels 16 to 28% as aescin).	Main active material of the extract. Animal and cell studies show anti-edema, anti-inflammatory and venotonic actions; low oral absorption in rats. ^{45 49 13 40}	Laboratory research
Protoescigenin (aglycone of escin, used for standardisation) PubChem 15560300	triterpene	Seed	Used as the calculation reference for triterpene glycoside content in the EU monograph. ^{45 49}	Laboratory research
Esculin (aesculin) PubChem 5281417	coumarin glycoside	Bark especially (25.89 to 38.94 mg/g dry weight in commercial bark samples); also made elsewhere in the plant 25.89 to 38.94 mg/g dry weight in commercial bark	A coumarin derivative. Contact dermatitis to a horse chestnut extract (esculin) has been reported (1980). Lab work on isolated esculin in other settings was not reviewed. Its role as the toxic part of raw plant material is NOT verified. ^{24 33 49 7}	Laboratory research
Esculetin (aglycone of esculin) PubChem 5281416	coumarin	Not verified	Not reviewed for this plant. ⁴⁹	Laboratory research
Fraxin PubChem 5273568	coumarin glycoside	Bark (12.58 to 17.13 mg/g dry weight in commercial samples) 12.58 to 17.13 mg/g	Measured with esculin in bark; activity not reviewed. ^{24 49}	Laboratory research
(-)-Epicatechin PubChem 72276	flavan-3-ol	Bark (10.42 to 13.96 mg/g dry weight in commercial samples) 10.42 to 13.96 mg/g	Measured in bark; activity not reviewed. ^{24 49}	Laboratory research
Quercetin and kaempferol glycosides (flavonols) PubChem 5280343	flavonoids	Seed (a seed extract in a rat study had quercetin glucuronide as its main compound)	Not shown to carry the clinical effect. ^{49 31}	Laboratory research

Mechanisms, receptors and pathways

Target or pathway	Gene or receptor	What was found	Level
Vein tone and capillary filtration rate	Not established	The EU monograph states that the exact mechanism is not known, but preclinical and clinical studies indicate an effect on venous tone and capillary filtration rate. In 22 CVI patients a single dose lowered the capillary filtration coefficient by 22% (human, small). ^{45 2}	Human data
Endothelial leakiness	AQP1 (aquaporin-1); HMGB1-induced	In cultured vessel-lining cells escin reduced leakiness caused by the inflammatory protein HMGB1 and lowered AQP1. ⁶	Laboratory research
Anti-edema, anti-inflammatory and venotonic actions	Platelet endothelial cell-adhesion molecule-1 (PECAM-1) and others	A review reports that escin reduces vascular permeability in inflamed tissue in animal models, tightens isolated human saphenous veins in vitro, and prevents hypoxia-induced disruption of PECAM-1 expression. ¹³	Animal research
Red blood cell membranes	Membrane lipids	At 15 to 60 microgram/mL escin broke human red blood cells and increased membrane fluidity; the main target seems to be membrane lipids. ¹⁴	Laboratory research
Liver drug-handling enzymes	CYP1A2, CYP2C9, CYP3A4	Intravenous aescin induced CYP1A2 and inhibited CYP2C9 and CYP3A4 in rats. ¹⁶	Animal research
Kidney and liver cell injury by sodium aescinate	Nrf2, FSP1, CTH, GPX4 pathways (ferroptosis)	Injectable sodium aescinate (from related seeds) caused ferroptosis in kidney and liver cells in mice and cell lines. ^{44 26 43}	Animal research

Absorption, metabolism and elimination

Absorption: In rats, oral bioavailability of escin Ib and isoescin Ib was below 2% (very poor absorption). In 18 healthy volunteers two formulations of seed extract (slow-release and not) were bioequivalent for beta-aescin blood levels, and absorption was lower at night than by day.
Distribution: Not found in humans.
Metabolism: In rats, escin Ib and isoescin Ib convert into each other in the body. Human metabolism not found.
Elimination: In 1977 rat work, injected aescin was cleared by the kidneys at about 13% of creatinine clearance, ruling out tubular secretion; about half did not bind plasma proteins in the test tube. Human elimination not found.
Bioavailability: Rat: below 2% for the pure isomers by mouth. Human oral bioavailability not established in the abstracts read; one validated method measured four escin isomers in human plasma after 60 mg of sodium aescinate tablets, but the abstract gives no results.

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Isolated compounds versus whole extracts

The clinical studies use whole standardised seed extract (HCSE), and the proof for benefit is for the extract, not for pure escin. Escin is the best-studied component, and trials of escin gels and escin by mouth or drip exist, but results with escin alone cannot be assumed for the whole extract and the reverse. The toxic portion of raw plant material must be kept out of extracts, so home-made preparations are not equivalent to standardised extract. Sodium aescinate, an injectable salt used in China, is a different product again.

Nutritional composition

A nutrient table is not meaningful for the medicinal use: standardised seed extracts are taken for their saponins, not for vitamins or minerals. Raw conkers are not a food.

15benefits and uses looked at

49studies and sources checked

Moderate certaintybest evidence rating found

10lab markers tracked in trials

2 moderate certainty1 mixed findings5 low certainty5 very low certainty2 not enough evidence

What was looked at

The 15 benefits and uses checked for Horse Chestnut, each with how strong the evidence is. Tap one to open it.

Chronic venous insufficiency: overall signs and symptomsModerate certainty
Chronic venous insufficiency: leg swelling (edema)Moderate certainty
Chronic venous insufficiency: leg painLow certainty
Heavy legs, itching and calf crampsLow certainty
Compared with compression stockingsLow certainty
Does stage of disease matter?Mixed findings
Venous leg ulcersNot enough evidence
Compared with other venous-health productsVery low certainty
Hemorrhoids (bleeding and swelling)Low certainty
Bruises and sports injuries (gel)Low certainty
Swelling and pain after surgeryVery low certainty
Gut recovery after bowel surgery (escin by drip)Very low certainty
Male fertility with varicoceleVery low certainty
Skin health in diabetic microcirculation (cream)Very low certainty
Irritable bowel syndrome and other usesNot enough evidence

Lab markers tracked in the studies

Lower leg volume (mL)Leg pain on a 100 mm visual analogue scaleCapillary filtration coefficientLower leg circumferenceHealed venous leg ulcers (number)Time until bleeding stops (days)Recurrence of hemorrhoid bleeding at 3 monthsPain on pressure (tenderness) over 6 hoursTime to passing gas after surgery (hours)Sperm density improvement rate

What is Horse Chestnut good for?

The main proposed uses and how strong the human evidence is for each. "Moderate" is the best rating any use reached. "Very low" and "insufficient" mean few, small or combination-product studies. These ratings are ours unless a review gave its own.

Chronic venous insufficiency: overall symptomsModerate certaintyTwo reviews of placebo-controlled trials found that standardised horse chestnut seed extract eased swelling, pain and itching in weak leg veins over a few weeks. The EU treats it as a well-established use. The trials are mostly small, older and short. Leg swelling (edema)Moderate certaintyPooled trials found legs about 30 to 45 mL smaller than with placebo. In the largest trial (240 people, 12 weeks), swelling fell about as much as with class II compression stockings. Leg painLow certaintyMost placebo-controlled trials reported less pain, but only one trial supplied a pooled number. Heavy legs, itching and calf crampsLow certaintyItching improved more than with placebo in one review. The evidence for heavy legs and calf cramps was not strong enough to say. Compared with compression stockingsLow certaintyOne large trial found similar swelling reduction. This does not mean the extract can replace stockings for everyone. Early versus advanced vein diseaseMixed findingsOne report found the extract worked like stockings in early disease, but not better than placebo in advanced disease. Venous leg ulcersNot enough evidenceIn one small trial the extract did not heal ulcers faster than placebo. Versus other venous productsVery low certaintySmall head-to-head trials gave mixed results, and Italian experts did not agree on using horse chestnut alone. HemorrhoidsLow certaintyTwo trials from one Thai team found that adding escin to a flavonoid medicine stopped bleeding about two days sooner and cut recurrence. Escin was not tested alone. Bruises and sports injuries (gel)Low certaintyEscin combination gels eased pain on pressure after sports injuries more than placebo gel. They also contain a salicylate and sometimes heparin. Swelling and pain after surgeryVery low certaintyCombination products that included escin helped some outcomes after wisdom tooth surgery and vein ablation. Escin alone was not tested. Gut recovery after bowel surgery (escin by drip)Very low certaintyA small pilot using escin by vein drip shortened time to passing gas. This is an injected product. Male fertility with varicoceleVery low certaintyOne Chinese trial found better sperm density with escin, but it was not placebo-controlled and reported no pregnancies. Skin health in diabetes (cream)Very low certaintyOne small, non-randomised registry found better skin blood flow with an aescin cream. Irritable bowel syndrome and other usesNot enough evidenceNCCIH says there is not enough information for irritable bowel syndrome or other uses.

Benefits, one by one

Each card is a research question, not a promise. Tap a goal to filter. Open a card to see the studies, doses and limits.

Chronic venous insufficiency: overall signs and symptoms

Moderate certainty

In people with chronic venous insufficiency (weak leg veins that cause swelling, heaviness and pain), standardised horse chestnut seed extract eased symptoms compared with placebo over a few weeks. It is the best-supported use of this herb, and still not backed by large modern trials.

5 studiesStudies used standardised seed extracts (HCSE, often adjusted to aesc…

Studies, doses and limits

What the trials found

The Cochrane review (Pittler and Ernst, 2012) of oral horse chestnut seed extract (HCSE) alone versus placebo or a reference treatment concluded that CVI signs and symptoms improved and that the extract is an efficacious and safe short-term treatment, with caveats. An earlier meta-analysis (Siebert 2002; 13 randomised trials, 1,051 people, plus 3 observational studies, 10,725 people) agreed. NCCIH and the EU monograph both cite this evidence (17 studies). The EU treats the standardised extract as a well-established use for CVI.

Results

Overall improvement in swelling, pain and itching versus placebo in short trials; severe side effects were not reported.

Effect sizes as reported

Cochrane: leg volume 32.1 mL less than placebo (95% CI 13.49 to 50.72; 6 trials, n=502); leg pain 42.4 mm lower on a 100 mm scale in one trial (CI 34.9 to 49.9). Siebert: edema improvement 1.5-fold more likely (CI 1.2 to 1.9).

Why this rating

No GRADE rating is given in the abstracts read. Our rating: moderate because pooled results agree across two reviews and a well-established EU use exists, but the trials are mostly small, short (up to about 12 weeks) and decades old, the reviewers ask for larger definitive trials, and some trial teams were company-linked.

Form and dose studied

Studies used standardised seed extracts (HCSE, often adjusted to aescin), not raw seed, bark or leaf. Raw seed, bark, leaf and flower are unsafe by mouth (NCCIH). Doses and which extract were used differ between trials; ask a doctor or pharmacist about amounts.

Who was studied

Adults with CVI, mostly mild to moderate.

Limits

Short trials. Older trials. Search ended in 2012. Different extracts and doses pooled. Only abstracts were read.

Why researchers looked

Chronic venous insufficiency (CVI) is common, and compression stockings are often uncomfortable, so people look for a pill. Horse chestnut seed extract is the herb most studied for it.

Traditional use

Horse chestnut seed has been used in Europe for leg and vein complaints for a long time. NCCIH lists traditional use for arthritis, pain and swelling, menstrual cramps and hemorrhoids. The EU has approved standardised seed extracts for chronic venous insufficiency.

Proposed mechanism Preliminary mechanism

Lab and animal work suggests escin, the main saponin group in the seed, tightens vein walls and makes the tiny vessels leak less fluid. In isolated human veins it increased tone, and in cell tests it reduced leakiness caused by inflammation. The exact way it works in people is not known (EU monograph).

A proposed mechanism does not show that the effect happens in people.

Sudden swelling of one leg, severe pain, skin inflammation, hardened tissue or ulcers should be checked by a doctor, not treated with a supplement (EU monograph).

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Chronic venous insufficiency: leg swelling (edema)

Moderate certainty

Several trials measured leg volume and found less swelling with horse chestnut seed extract than with placebo. The size of the change is small to moderate (tens of millilitres).

5 studiesStudies used standardised seed extracts (HCSE, often adjusted to aesc…

Studies, doses and limits

What the trials found

Cochrane pooled 6 placebo-controlled trials (n=502) for leg volume. The Lancet trial (Diehm 1996; 240 people, 12 weeks) found lower leg volume fell 43.8 mL with HCSE, 46.7 mL with compression stockings and rose 9.8 mL with placebo. A 40-person double-blind trial (Diehm 1992) found a significant edema-reducing effect by plethysmography, and a 22-person crossover trial (Bisler 1986) found the capillary filtration coefficient fell 22% three hours after a dose.

Results

Smaller legs by tens of millilitres versus placebo over weeks; a single dose already reduced a lab measure of fluid leaking from vessels.

Effect sizes as reported

Cochrane WMD 32.1 mL (CI 13.49 to 50.72); Siebert 46.4 mL (CI 11.3 to 81.4); Diehm 1996 HCSE -43.8 mL versus placebo +9.8 mL.

Why this rating

Consistent direction in two reviews and in the largest trial, but the pooled intervals are wide, trials are old and short, and whether a 30 to 45 mL change matters to patients is not settled.

Form and dose studied

Studies used standardised seed extracts (HCSE, often adjusted to aescin), not raw seed, bark or leaf. Raw seed, bark, leaf and flower are unsafe by mouth (NCCIH).

Who was studied

Adults with CVI and leg swelling.

Limits

Volume change is a measurement, not proof the person feels better. Only abstracts were read.

Why researchers looked

Swelling is the measurable sign most trials used.

Traditional use

Proposed mechanism Preliminary mechanism

A proposed mechanism does not show that the effect happens in people.

Sudden one-sided swelling can be a blood clot and needs urgent care.

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Chronic venous insufficiency: leg pain

Low certainty

Most placebo-controlled trials reported less leg pain with horse chestnut seed extract, but the pain data come from fewer trials and are less certain than the swelling data.

2 studiesStudies used standardised seed extracts (HCSE, often adjusted to aesc…

Studies, doses and limits

What the trials found

Cochrane: leg pain was assessed in 7 placebo-controlled trials; 6 reported a significant reduction versus placebo and 1 a significant improvement versus baseline. Only one trial supplied a pooled-style number (42.4 mm on a 100 mm scale). Siebert 2002 found leg pain improvement 4.1-fold more likely, but the confidence interval almost included no effect (0.98 to 16.8).

Results

Less pain than placebo in most trials.

Effect sizes as reported

Cochrane: WMD 42.4 mm (CI 34.9 to 49.9; one trial). Siebert: 4.1-fold (CI 0.98 to 16.8).

Why this rating

The direction is consistent, but one trial supplies the number and the other review has a very wide interval; pain is subjective in short trials.

Form and dose studied

Studies used standardised seed extracts (HCSE, often adjusted to aescin), not raw seed, bark or leaf. Raw seed, bark, leaf and flower are unsafe by mouth (NCCIH).

Who was studied

Adults with CVI.

Limits

Pain scales are subjective; not every trial reported numbers in the abstract.

Why researchers looked

Leg pain and aching is the symptom that sends most people to treatment.

Traditional use

Proposed mechanism Preliminary mechanism

A proposed mechanism does not show that the effect happens in people.

See key safety points.

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Heavy legs, itching and calf cramps

Low certainty

Itching improved more than with placebo in one review. For tired, heavy legs and calf cramps the pooled evidence was not strong enough to say.

2 studiesStudies used standardised seed extracts (HCSE, often adjusted to aesc…

Studies, doses and limits

What the trials found

Siebert 2002 found improvement in itching 1.7-fold more likely than with placebo (CI 0.01 to 3.0, a very wide range) and said there was insufficient evidence to show an effect on leg fatigue/heaviness or calf cramps in the randomised trials. The observational studies in that review showed gains in leg fatigue/heaviness. A review of 5 studies of one fresh-plant extract reported relief of heaviness and itching.

Results

Possible itching benefit; heaviness and cramps unproven in trials.

Effect sizes as reported

Itching: 1.7-fold more likely (CI 0.01 to 3.0).

Why this rating

Wide intervals and no firm trial result for heaviness and cramps; the 5-study review covers one product.

Form and dose studied

Studies used standardised seed extracts (HCSE, often adjusted to aescin), not raw seed, bark or leaf. Raw seed, bark, leaf and flower are unsafe by mouth (NCCIH).

Who was studied

Adults with CVI.

Limits

Small numbers; mixed outcomes.

Why researchers looked

These are everyday CVI symptoms that people want help with.

Traditional use

Proposed mechanism Preliminary mechanism

A proposed mechanism does not show that the effect happens in people.

See key safety points.

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Compared with compression stockings

Low certainty

One large trial found the extract and class II compression stockings reduced leg swelling by similar amounts over 12 weeks. That does not mean the pill replaces stockings for everyone.

3 studiesStudies used standardised seed extracts (HCSE, often adjusted to aesc…

Studies, doses and limits

What the trials found

Diehm 1996 (240 people, 12 weeks, partly blinded): leg volume of the more affected leg fell 43.8 mL on HCSE and 46.7 mL on stockings and rose 9.8 mL on placebo; the two were equivalent in the trial design. Cochrane notes that one trial suggested HCSE may be as effective as stockings. In the other study pair (Ottillinger and Greeske 2001) HCSE and stockings matched each other in early CVI.

Results

Similar swelling reduction to stockings in early to moderate disease in one large trial.

Effect sizes as reported

HCSE -43.8 mL vs compression -46.7 mL vs placebo +9.8 mL.

Why this rating

Based mainly on one trial, partly unblinded (stockings cannot be hidden), and the authors note stockings could not be proven as the standard in that design.

Form and dose studied

Studies used standardised seed extracts (HCSE, often adjusted to aescin), not raw seed, bark or leaf. Raw seed, bark, leaf and flower are unsafe by mouth (NCCIH).

Who was studied

Adults with CVI.

Limits

Only one large trial. Stockings may still be needed in advanced disease.

Why researchers looked

Many people cannot tolerate stockings.

Traditional use

Proposed mechanism Preliminary mechanism

A proposed mechanism does not show that the effect happens in people.

Do not stop prescribed compression without advice.

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Does stage of disease matter?

Mixed findings

Results hint that the extract works best in early disease. In advanced disease (swollen skin changes, healed ulcers) compression worked and the extract did not beat placebo in one report.

1 studiesStudies used standardised seed extracts (HCSE, often adjusted to aesc…

Studies, doses and limits

What the trials found

Ottillinger and Greeske (2001) report two studies. In early CVI (grade I) HCSE and compression were both better than placebo and equal. In advanced CVI (grade II and IIIa) compression beat placebo, HCSE did not; HCSE did better in grade II than IIIa. The authors suggest starting drug treatment early.

Results

Better for earlier stages; unproven for advanced.

Effect sizes as reported

Numbers not given in the abstract.

Why this rating

Two studies in one report, sample sizes not in the abstract; one supports benefit in early disease, the other does not in advanced disease.

Form and dose studied

Studies used standardised seed extracts (HCSE, often adjusted to aescin), not raw seed, bark or leaf. Raw seed, bark, leaf and flower are unsafe by mouth (NCCIH).

Who was studied

Early and advanced CVI.

Limits

Sample sizes not in the abstract.

Why researchers looked

Doctors need to know who might benefit.

Traditional use

Proposed mechanism Preliminary mechanism

A proposed mechanism does not show that the effect happens in people.

Advanced CVI, ulcers and skin changes need medical care.

²³

Venous leg ulcers

Not enough evidence

In a small trial, horse chestnut seed extract did not heal ulcers faster than placebo. It may reduce slough and dressing changes, but this is uncertain.

1 studiesStudies used standardised seed extracts (HCSE, often adjusted to aesc…

Studies, doses and limits

What the trials found

Leach 2006: 54 people (27 per group), 12 weeks, triple-blind. No significant difference in healed ulcers or in wound area, depth, volume, pain or exudate; wound slough (p=0.045) and dressing changes at week 12 (p=0.009) differed. The authors say the trial was underpowered.

Results

No proven faster healing.

Effect sizes as reported

No difference in healed ulcers.

Why this rating

One small trial with null main results and two possibly chance findings.

Form and dose studied

Studies used standardised seed extracts (HCSE, often adjusted to aescin), not raw seed, bark or leaf. Raw seed, bark, leaf and flower are unsafe by mouth (NCCIH).

Who was studied

Adults with venous leg ulcers.

Limits

Small; many outcomes.

Why researchers looked

Leg ulcers are a serious complication of CVI.

Traditional use

Proposed mechanism Preliminary mechanism

A proposed mechanism does not show that the effect happens in people.

Leg ulcers should be treated by a clinician.

²¹

Compared with other venous-health products

Very low certainty

Head-to-head trials against oxerutins and Pycnogenol were small and not designed to prove equality; Pycnogenol did better in one open study. A 2025 Italian expert group did not agree on using horse chestnut alone.

3 studiesStudies used standardised seed extracts (HCSE, often adjusted to aesc…

Studies, doses and limits

What the trials found

Rehn 1996 (137 postmenopausal women): oxerutins 1000 mg a day were equivalent or better than horse chestnut extract for reducing leg volume; the oxerutin maker was involved. Koch 2002 (40 people, open, 4 weeks): Pycnogenol reduced leg circumference and symptoms; horse chestnut seed extract only moderately and not significantly. The SIAPAV Delphi (2025; 21 specialists) reached no consensus on horse chestnut used alone.

Results

No evidence it beats other venous products; some trials suggest it is less effective.

Why this rating

Small trials, open design, company links, short follow-up.

Form and dose studied

Studies used standardised seed extracts (HCSE, often adjusted to aescin), not raw seed, bark or leaf. Raw seed, bark, leaf and flower are unsafe by mouth (NCCIH).

Who was studied

Adults with CVI.

Limits

No placebo in the comparison phases.

Why researchers looked

People wonder which venous supplement is best.

Traditional use

Proposed mechanism Preliminary mechanism

A proposed mechanism does not show that the effect happens in people.

See key safety points.

^{28 19 3}

Hemorrhoids (bleeding and swelling)

Low certainty

Two trials from one team in Thailand found that adding escin to a standard hemorrhoid flavonoid medicine stopped bleeding sooner and reduced recurrence. Escin was not tested on its own against placebo.

3 studiesEscin 120 mg a day was used in the 2026 trial. Ask a doctor or pharma…

Studies, doses and limits

What the trials found

Sanmee 2024 (randomised, Chiang Mai University): aescin plus micronized purified flavonoid fraction (MPFF) versus MPFF alone in grade 1 and 2 acute hemorrhoids; bleeding stopped in 2 versus 4 days and the mass effect resolved in 4 versus 5 days; fewer treatment failures. Vipudhamorn 2026 (double-blind, placebo, 108 people who stopped bleeding): recurrence at 3 months 7.02% with escin versus 23.52% with placebo (hazard ratio reported 3.95, P=0.009); median time to bleeding stopping 2 versus 4 days; no adverse events.

Results

Faster control of bleeding and fewer recurrences when escin was added to MPFF in grade 1 to 2 bleeding hemorrhoids.

Effect sizes as reported

Recurrence at 3 months 7.02% vs 23.52%; bleeding stops 2 days vs 4.

Why this rating

Two randomised trials point the same way, but both are from one centre, both are add-on designs, both used the same flavonoid drug, and the first abstract is unclear about group size. No independent replication.

Form and dose studied

Escin 120 mg a day was used in the 2026 trial. Ask a doctor or pharmacist about amounts.

Who was studied

Adults with grade 1 or 2 internal hemorrhoids.

Limits

One research group; add-on to another drug; short follow-up (90 days); only abstracts read.

Why researchers looked

Hemorrhoids are swollen veins, so a vein-tightening herb is a natural idea. Traditional use of horse chestnut for hemorrhoids is listed by NCCIH.

Traditional use

NCCIH lists hemorrhoids among traditional uses of horse chestnut seed extract.

Proposed mechanism Preliminary mechanism

Lab and animal work suggests escin reduces vessel leakiness and inflammation in tissue, which could limit swelling and bruising. This has not been shown to be the cause of any benefit in the people studied.

A proposed mechanism does not show that the effect happens in people.

Rectal bleeding needs a doctor to rule out other causes, especially over age 45 or if it persists.

^{30 35 48}

Bruises and sports injuries (gel)

Low certainty

In trials of Reparil-type gels (one by the maker), escin combination gels eased pain on pressure after blunt sports injuries more than placebo gel. These gels also contain a salicylate and sometimes heparin.

4 studiesTopical gel; escin 1% to 2% in the combination gels.

Studies, doses and limits

What the trials found

Wetzel 2002 (158 athletes, within 2 hours of injury): 1% and 2% escin gels with salicylate and heparin beat placebo on pain on pressure over 6 hours. Pabst 2001 (126 people): three Reparil gels beat placebo gel (p=0.0004 each); no adverse events. Calabrese and Preston 1993: a 2% escin gel versus placebo reduced tenderness of an experimentally induced bruise in healthy volunteers (abstract has no numbers).

Results

Faster pain relief on pressure after sports bruises with combination gels.

Effect sizes as reported

Wetzel: effect 5.7 and 5.9 kp h/cm2 versus placebo (CI 2.9 to 8.5 and 2.9 to 8.8).

Why this rating

Positive placebo-controlled trials, but the gels are combinations (so escin alone is not proven), at least one is from the manufacturer, and follow-up was 24 hours.

Form and dose studied

Topical gel; escin 1% to 2% in the combination gels.

Who was studied

Healthy adults with sports injuries or experimental bruises.

Limits

Combination products; short; industry-linked; one trial has no numbers in the abstract.

Why researchers looked

Escin is thought to reduce leakiness of small vessels, which may limit bruising and swelling. The EU lists a traditional use for bruises.

Traditional use

EU traditional use for relief of signs of bruises, such as local edema and haematoma.

Proposed mechanism Preliminary mechanism

A proposed mechanism does not show that the effect happens in people.

The EU monograph says not to use on broken skin, around the eyes or on mucous membranes; skin itching and redness are reported.

^{38 25 5 45}

Swelling and pain after surgery

Very low certainty

A mixed plant tablet that included escin eased pain after wisdom tooth surgery, and a gel with escin helped swelling after vein ablation. Because these products contain other ingredients, escin cannot be given the credit.

2 studiesCombination tablet or gel.

Studies, doses and limits

What the trials found

Isola 2019 (82 people, triple-blind): a combination of baicalin, bromelain and escin 30 mg lowered pain at 12, 24 and 48 hours versus ibuprofen and placebo, but swelling and jaw stiffness did not differ. Kuznetsov 2025 (180 women, open, Russia): a topical gel with escin, heparin and essential phospholipids reduced edema in 91.7% (grade 3) versus 72.7% with no extra treatment and 76.9% with heparin gel, and reduced the "string" tightness after radiofrequency ablation of a leg vein.

Results

Combination products reduced some pain or swelling after procedures.

Effect sizes as reported

Pain lower at 12 h (p<0.001), 24 h (p=0.010), 48 h (p=0.048); edema decrease 91.7% vs 72.7% vs 76.9%.

Why this rating

Escin is one of several ingredients in both products; one trial is open and unblinded; swelling did not differ in the dental trial.

Form and dose studied

Combination tablet or gel.

Who was studied

Adults after third molar surgery; women after vein ablation.

Limits

Combination products; no escin-alone trial; abstracts only.

Why researchers looked

Escin is studied for reducing swelling after trauma and surgery.

Traditional use

EU traditional use includes local edema.

Proposed mechanism Preliminary mechanism

A proposed mechanism does not show that the effect happens in people.

See key safety points.

^{17 20}

Gut recovery after bowel surgery (escin by drip)

Very low certainty

In a small pilot trial in China, escin given by drip into a vein shortened the time to passing gas and a bowel movement after colon surgery. This was an injected product, not a supplement.

1 studiesEscin by intravenous drip; not an oral supplement.

Studies, doses and limits

What the trials found

Xie 2009: 72 colorectal cancer patients, four groups of 18 (placebo or escin 5, 15 or 25 mg a day by vein for up to 7 days). Time to passing gas was shorter by 10.75 h (15 mg, p=0.036) and 17.31 h (25 mg, p=0.022); time to bowel movement shorter by 23.44 h and 23.83 h. Bowel sounds did not differ significantly; 5 mg did not differ from placebo.

Results

Faster return of gut function with 15 and 25 mg given by drip.

Effect sizes as reported

Passing gas 10.75 h and 17.31 h sooner than placebo.

Why this rating

A pilot of 18 people per group; injected prescription-type product in China; no replication found.

Form and dose studied

Escin by intravenous drip; not an oral supplement.

Who was studied

Adults after colorectal cancer surgery.

Limits

Pilot; one centre; injection only.

Why researchers looked

Slow gut recovery after surgery lengthens hospital stays.

Traditional use

No traditional use.

Proposed mechanism Animal research

In mice escin sped up gut transit (as stated in the study introduction); human mechanism unknown.

A proposed mechanism does not show that the effect happens in people.

Injected sodium aescinate has been linked to kidney and liver injury in clinical use and lab work (see safety file).

⁴¹

Male fertility with varicocele

Very low certainty

In one Chinese trial, men with varicocele and low sperm counts who took escin for two months had a higher rate of sperm density improvement than controls. Evidence is too thin to rely on.

2 studiesEscin 60 mg a day by mouth for 2 months in the trial.

Studies, doses and limits

What the trials found

Fang 2010: 219 men with varicocele-associated infertility were assigned to control, surgery or escin (106 men; 60 mg a day by mouth for 2 months). Sperm density improved in 57.5% on escin, 68.8% after surgery and 38.5% in controls (escin versus control P<0.05). Sperm motility improvement with escin (55.7%) was not significantly different from control (46.2%). NCCIH says there is not enough information to draw conclusions.

Results

Better sperm density in one study; no pregnancy outcomes in the abstract.

Effect sizes as reported

Density improvement 57.5% vs 38.5% control (surgery 68.8%).

Why this rating

One trial, unclear control treatment, not placebo-controlled, no pregnancy outcomes in the abstract.

Form and dose studied

Escin 60 mg a day by mouth for 2 months in the trial.

Who was studied

Chinese men with varicocele-associated infertility.

Limits

One trial; fertility outcomes not reported.

Why researchers looked

A varicocele is a swollen vein in the scrotum, so vein herbs have been tried.

Traditional use

NCCIH: promoted for male infertility with varicocele; very little research.

Proposed mechanism Preliminary mechanism

A proposed mechanism does not show that the effect happens in people.

Mild side effects were few and eased by taking after meals.

^{12 48}

Skin health in diabetic microcirculation (cream)

Very low certainty

One small registry in diabetes found better skin blood flow with an aescin cream added to standard foot care. It was not randomised.

1 studiesTopical aescin cream.

Studies, doses and limits

What the trials found

Hu 2016: 63 patients with moderate diabetic microangiopathy chose standard care (31) or standard care plus an aescin-based cream (32) for 8 weeks; both groups improved, the cream group more, on skin blood flow and foot skin condition.

Results

Better skin measures with the cream.

Effect sizes as reported

Numbers not given in the abstract.

Why this rating

Not randomised, small, branded formulation, abstract gives no numbers.

Form and dose studied

Topical aescin cream.

Who was studied

Adults with diabetes and microangiopathy.

Limits

Registry design; 8 weeks; only abstract read.

Why researchers looked

People with diabetes are prone to foot ulcers.

Traditional use

No traditional use.

Proposed mechanism Preliminary mechanism

A proposed mechanism does not show that the effect happens in people.

No diabetes drug changes were studied; see safety file for diabetes medicines.

¹⁵

Irritable bowel syndrome and other uses

Not enough evidence

NCCIH says there is not enough information on irritable bowel syndrome. Other claims (cancer, obesity, liver protection) are lab or animal work only.

1 studiesNot applicable.

Studies, doses and limits

What the trials found

NCCIH (read 2026-10-25): small amounts of research on male infertility and irritable bowel syndrome; not enough information for conclusions. We found no human trial of horse chestnut alone for irritable bowel in the searches we ran.

Results

No proven benefit.

Why this rating

No trial of horse chestnut alone found for these uses.

Limits

No human data.

Why researchers looked

NCCIH notes the extract is promoted for irritable bowel syndrome and other conditions.

Traditional use

Traditional use for arthritis, pain, menstrual cramps listed by NCCIH.

Proposed mechanism Preliminary mechanism

Not established.

A proposed mechanism does not show that the effect happens in people.

See key safety points.

⁴⁸

Connections to the rest of health

How Horse Chestnut connects to the rest of our health knowledge graph. Every link says what kind of connection it is. A safety link (for example to the liver) is a warning, not a benefit. A study that merely mentions a topic never creates a benefit link.

Explore every connection: goals, body systems, organs, symptoms, genes

Kind of connection Connected to Search

A. Wellness goals

Connected to	Kind of connection	Evidence status	Context	Studies
Inflammation Balance	Demonstrated clinical effect	Moderate certainty	Chronic venous insufficiency: overall signs and symptoms: In people with chronic venous insufficiency (weak leg veins that cause swelling, heaviness and pain), standardised horse chestnut seed extract eased symptoms compared with placebo over a few weeks. It is the best-supported use of this herb, and still not backed by large modern trials. Chronic venous insufficiency: leg swelling (edema): Several trials measured leg volume and found less swelling with horse chestnut seed extract than with placebo. The size of the change is small to moderate (tens of millilitres).	^{27 32 45 48 34 11 10 2 23}
Inflammation Balance	Potential benefit	Low certainty	Heavy legs, itching and calf cramps: Itching improved more than with placebo in one review. For tired, heavy legs and calf cramps the pooled evidence was not strong enough to say. Does stage of disease matter?: Results hint that the extract works best in early disease. In advanced disease (swollen skin changes, healed ulcers) compression worked and the extract did not beat placebo in one report.	^{32 34 23 28 19 3}
Healthy Skin	Potential benefit	Not enough evidence	Venous leg ulcers: In a small trial, horse chestnut seed extract did not heal ulcers faster than placebo. It may reduce slough and dressing changes, but this is uncertain.	²¹
Digestive Support	Potential benefit	Low certainty	Hemorrhoids (bleeding and swelling): Two trials from one team in Thailand found that adding escin to a standard hemorrhoid flavonoid medicine stopped bleeding sooner and reduced recurrence. Escin was not tested on its own against placebo. Gut recovery after bowel surgery (escin by drip): In a small pilot trial in China, escin given by drip into a vein shortened the time to passing gas and a bowel movement after colon surgery. This was an injected product, not a supplement.	^{30 35 48 41}
Muscle Recovery	Potential benefit	Low certainty	Bruises and sports injuries (gel): In trials of Reparil-type gels (one by the maker), escin combination gels eased pain on pressure after blunt sports injuries more than placebo gel. These gels also contain a salicylate and sometimes heparin. Swelling and pain after surgery: A mixed plant tablet that included escin eased pain after wisdom tooth surgery, and a gel with escin helped swelling after vein ablation. Because these products contain other ingredients, escin cannot be given the credit.	^{38 25 5 45 17 20}
Fertility Support	Potential benefit	Very low certainty	Male fertility with varicocele: In one Chinese trial, men with varicocele and low sperm counts who took escin for two months had a higher rate of sperm density improvement than controls. Evidence is too thin to rely on.	^{12 48}
Mens Vitality	Potential benefit	Very low certainty	Male fertility with varicocele: In one Chinese trial, men with varicocele and low sperm counts who took escin for two months had a higher rate of sperm density improvement than controls. Evidence is too thin to rely on.	^{12 48}
Blood Sugar Balance	Potential benefit	Very low certainty	Skin health in diabetic microcirculation (cream): One small registry in diabetes found better skin blood flow with an aescin cream added to standard foot care. It was not randomised.	¹⁵
Gut Health	Traditional use	Not enough evidence	Irritable bowel syndrome and other uses: NCCIH says there is not enough information on irritable bowel syndrome. Other claims (cancer, obesity, liver protection) are lab or animal work only.	⁴⁸
Digestive Support	Traditional use	Not enough evidence	Irritable bowel syndrome and other uses: NCCIH says there is not enough information on irritable bowel syndrome. Other claims (cancer, obesity, liver protection) are lab or animal work only.	⁴⁸

B. Body systems

Connected to	Kind of connection	Evidence status	Context	Studies
Cardiovascular system	Adverse effect or risk	Low certainty	Dizziness and sudden leg swelling warrant care; do not self-treat clots. Preparation or compound: Standardised seed extract	⁴⁵
Digestive system	Adverse effect or risk	Low certainty	Stomach upset, nausea. Preparation or compound: Standardised seed extract	^{45 48}
Immune system	Adverse effect or risk	Low certainty	Allergic reactions including anaphylaxis; mugwort pollen link (title only). Preparation or compound: Seed extract	^{18 8}
Cardiovascular System	Biological association	Moderate certainty	Studied for: Chronic venous insufficiency: overall signs and symptoms Studied for: Chronic venous insufficiency: leg swelling (edema)	^{27 32 45 48 34 11 10 2 23 21 28 19 3 30 35 15}
Integumentary System	Biological association	Not enough evidence	Studied for: Venous leg ulcers Studied for: Bruises and sports injuries (gel)	^{21 38 25 5 45 15}
Digestive System	Biological association	Low certainty	Studied for: Hemorrhoids (bleeding and swelling) Studied for: Gut recovery after bowel surgery (escin by drip)	^{30 35 48 41}
Musculoskeletal System	Biological association	Low certainty	Studied for: Bruises and sports injuries (gel) Studied for: Swelling and pain after surgery	^{38 25 5 45 17 20}
Reproductive System	Biological association	Very low certainty	Studied for: Male fertility with varicocele	^{12 48}

C. Body parts and organs

Connected to	Kind of connection	Evidence status	Context	Studies
Kidneys	Contraindication	Very low certainty	EU: consult a doctor in renal insufficiency; lab and case reports of kidney injury. Preparation or compound: Sodium aescinate (injection) and beta-aescin	^{36 44 26 45}
Liver	Adverse effect or risk	Very low certainty	Rare liver injury reported. Preparation or compound: Horse chestnut supplement	^{22 9}
Skin	Adverse effect or risk	Low certainty	Itching, redness, contact dermatitis. Preparation or compound: Topical extract	^{45 7}

E. Health conditions

Connected to	Kind of connection	Evidence status	Context	Studies
Pregnancy	Contraindication	Not enough evidence	Not recommended; no safety data. Preparation or compound: Any	^{45 48}
Breastfeeding	Contraindication	Not enough evidence	Not recommended; no safety data. Preparation or compound: Any	^{45 48}
Blood-thinner use	Drug or supplement interaction	Very low certainty	Theory-based caution only. Preparation or compound: Seed extract	¹
Diabetes medicines	Drug or supplement interaction	Not enough evidence	Animal blood sugar lowering; no human data. Preparation or compound: Seed saponin fractions	³¹
Chronic venous insufficiency	Demonstrated clinical effect	Moderate certainty	Modest short-term swelling and pain relief versus placebo. Preparation or compound: Standardised seed extract	^{27 32}
Hemorrhoids	Potential benefit	Low certainty	Faster bleeding control and fewer recurrences as an add-on. Preparation or compound: Escin plus MPFF	^{30 35}
Bruises and blunt injuries	Potential benefit	Low certainty	Combination gels eased pain on pressure. Preparation or compound: Escin/salicylate/heparin gels	^{38 25}
Kidney disease	Contraindication	Very low certainty	EU: consult a doctor in renal insufficiency. Preparation or compound: Seed extract; sodium aescinate	^{45 36}

I. Biomarkers

Connected to	Kind of connection	Evidence status	Context	Studies
Lower leg volume (mL)	Biological association	Moderate certainty	Measured in trials: lowered. A lab change is not the same as a health benefit.	^{27 11 32}
Leg pain on a 100 mm visual analogue scale	Biological association	Low certainty	Measured in trials: lowered. A lab change is not the same as a health benefit.	²⁷
Capillary filtration coefficient	Biological association	Low certainty	Measured in trials: lowered. A lab change is not the same as a health benefit.	²
Lower leg circumference	Biological association	Low certainty	Measured in trials: mixed. A lab change is not the same as a health benefit.	^{10 19}
Healed venous leg ulcers (number)	Biological association	Not enough evidence	Measured in trials: no-change. A lab change is not the same as a health benefit.	²¹
Time until bleeding stops (days)	Biological association	Low certainty	Measured in trials: lowered. A lab change is not the same as a health benefit.	^{30 35}
Recurrence of hemorrhoid bleeding at 3 months	Biological association	Low certainty	Measured in trials: lowered. A lab change is not the same as a health benefit.	³⁵
Pain on pressure (tenderness) over 6 hours	Biological association	Low certainty	Measured in trials: raised. A lab change is not the same as a health benefit.	^{38 25}
Time to passing gas after surgery (hours)	Biological association	Very low certainty	Measured in trials: lowered. A lab change is not the same as a health benefit.	⁴¹
Sperm density improvement rate	Biological association	Very low certainty	Measured in trials: raised. A lab change is not the same as a health benefit.	¹²

J. Genes, receptors and enzymes

Connected to	Kind of connection	Evidence status	Context	Studies
AQP1 (aquaporin-1)	Preliminary mechanism	In vitro	Escin lowered AQP1 and endothelial leakiness in cultured cells.	⁶
CYP1A2, CYP2C9, CYP3A4	Preliminary mechanism	Animal	Aescin induced CYP1A2 and inhibited CYP2C9 and CYP3A4 in rats (injected dose).	¹⁶
Aescin and aesculin biosynthesis genes (in Aesculus chinensis)	Preliminary mechanism	Other	Gene clusters (for example OCS6, CYP716A278) make aescin; seven genes make aesculin. This is a different species.	³³

K. Biological pathways

Connected to	Kind of connection	Evidence status	Context	Studies
Nrf2 pathway and ferroptosis (CTH, GPX4, FSP1)	Preliminary mechanism	Animal	Sodium aescinate suppressed Nrf2 signalling and triggered ferroptosis in kidney and liver cells.	^{44 43 26}

L. Active compounds

Connected to	Kind of connection	Evidence status	Context	Studies
Escin / aescin (mixture of triterpene saponins; isomers escin Ia, Ib, isoescin Ia, Ib)	Biological association	In vitro	Main active material of the extract. Animal and cell studies show anti-edema, anti-inflammatory and venotonic actions; low oral absorption in rats. Preparation or compound: Seed	^{45 49 13 40}
Protoescigenin (aglycone of escin, used for standardisation)	Biological association	In vitro	Used as the calculation reference for triterpene glycoside content in the EU monograph. Preparation or compound: Seed	^{45 49}
Esculin (aesculin)	Biological association	In vitro	A coumarin derivative. Contact dermatitis to a horse chestnut extract (esculin) has been reported (1980). Lab work on isolated esculin in other settings was not reviewed. Its role as the toxic part of raw plant material is NOT verified. Preparation or compound: Bark especially (25.89 to 38.94 mg/g dry weight in commercial bark samples); also made elsewhere in the plant	^{24 33 49 7}
Esculetin (aglycone of esculin)	Biological association	In vitro	Not reviewed for this plant. Preparation or compound: Not verified	⁴⁹
Fraxin	Biological association	In vitro	Measured with esculin in bark; activity not reviewed. Preparation or compound: Bark (12.58 to 17.13 mg/g dry weight in commercial samples)	^{24 49}
(-)-Epicatechin	Biological association	In vitro	Measured in bark; activity not reviewed. Preparation or compound: Bark (10.42 to 13.96 mg/g dry weight in commercial samples)	^{24 49}
Quercetin and kaempferol glycosides (flavonols)	Biological association	In vitro	Not shown to carry the clinical effect. Preparation or compound: Seed (a seed extract in a rat study had quercetin glucuronide as its main compound)	^{49 31}

Each connection is stored with the ingredient, the connected record, the kind of connection, the evidence status, the supporting studies, the preparation or compound involved, and a review date (last reviewed October 25, 2026).

Evidence at a glance: what changed in 10 lab markers

Tap a number to show only those markers. Counts are markers, not people.

Other6211

The evidence

The research centre for Horse Chestnut. Every record here was checked against PubMed or the publisher's page; we never list a study we have not verified.

Evidence by outcome

Chronic venous insufficiency: overall signs and symptoms 5 studies Moderate certainty Chronic venous insufficiency: leg swelling (edema) 5 studies · 302 people in trials Moderate certainty Chronic venous insufficiency: leg pain 2 studies Low certainty Heavy legs, itching and calf cramps 2 studies Low certainty Compared with compression stockings 3 studies · 240 people in trials Low certainty Does stage of disease matter? 1 study Mixed findings Venous leg ulcers 1 study · 54 people in trials Not enough evidence Compared with other venous-health products 3 studies · 137 people in trials Very low certainty Hemorrhoids (bleeding and swelling) 3 studies · 228 people in trials Low certainty Bruises and sports injuries (gel) 4 studies · 284 people in trials Low certainty Swelling and pain after surgery 2 studies · 262 people in trials Very low certainty Gut recovery after bowel surgery (escin by drip) 1 study · 72 people in trials Very low certainty Male fertility with varicocele 2 studies · 219 people in trials Very low certainty Skin health in diabetic microcirculation (cream) 1 study Very low certainty Irritable bowel syndrome and other uses 1 study Not enough evidence

Bars show how many studies we found for each outcome, not how well it works. People are added up across trials only (reviews are not added, to avoid double counting).

How we rate evidence

High certainty

Several well-run trials or reviews agree; further research is unlikely to change the picture much.

Moderate certainty

Good trials point the same way, but some doubt remains.

Low certainty

Small, short or inconsistent trials. The finding could change with better research.

Very low certainty

Very little or very weak human data. Treat as a possibility only.

Mixed findings

Trials or reviews disagree with each other.

Not enough evidence

Not enough human research to say either way.

Evidence against

Good research found no benefit, or found harm.

We take the reviewers' own risk-of-bias and GRADE statements where they exist, and otherwise judge from study size, design, consistency, directness and whether a product matches what is sold. Many publications do not make evidence high. Method note: We searched PubMed, the NIH NCCIH page and the EU herbal monograph (read in full), and recorded each study's design, people, product and result as reported. Only abstracts were read for the PubMed studies, and two records have no abstract. The EU assessment report, Commission E, WHO and the full LiverTox entry were not read. Ratings are ours unless a review gave its own.

Study library: every study we checked 49

Design Research type Plant part Year from Search

Study	Design	People	Product, dose, length	Result
Argento 2000 [Oral anticoagulants and medicinal plants. An emerging interaction]. Ann Ital Med Int · PMID 10920504	Review	Review of herbs that may change the effect of oral blood thinners (Italian)	Herbs including horse chestnut	The review lists horse chestnut among herbs that "reinforce warfarin action by heterogeneous mechanisms" and says they should not be used by people on blood thinners or antiplatelet drugs. It gives no study data on horse chestnut in the abstract. n/a (n/a) Methods, limits and funding Outcomes: Interaction with warfarin Limitations: 2000 narrative review in Italian; the abstract gives no trial or case data for horse chestnut. Low-quality evidence for this specific claim. Only the abstract was read. Funding and conflicts: Not stated Read: abstract
Bisler 1986 [Effects of horse-chestnut seed extract on transcapillary filtration in chronic venous insufficiency]. Dtsch Med Wochenschr · PMID 3527643 · DOI	Controlled trial	22 Patients with proven CVI (crossover trial)	HCSE standardised to aescin (Venostasin retard), two capsules of 50 mg aescin each seed 2 capsules (each 50 mg aescin; 600 mg extract) as a single dose 3 hours (single dose) · vs Identical-looking placebo capsule	Capillary filtration coefficient fell 22% three hours after HCSE and rose slightly after placebo (P=0.006). Intravascular volume fell 5% more after HCSE, not statistically significant. Capillary filtration coefficient -22% versus placebo (P=0.006) (Not given) Methods, limits and funding Outcomes: Capillary filtration coefficient and intravascular volume of the lower leg (venous-occlusion plethysmography) Limitations: Very small, single dose, a lab measure rather than how patients feel. Article in German; only the abstract was read. Funding and conflicts: Not stated in the abstract Read: abstract
Buso 2025 Delphi Consensus on the Role of Venoactive Nutraceuticals in the Management of Chronic Venous Disease: A Position Statement of the Italian Society of Angiology and Vascular Medicine (SIAPAV). Nutrients · PMID 41470775 · DOI	Consensus statement	21 21 Italian vascular specialists, 3-round Delphi (May to July 2025)	Venoactive nutraceuticals including horse chestnut mixed	The panel agreed on selected venoactive nutraceuticals across CVD stages and favoured combinations. No consensus was reached for horse chestnut (or ruscus, hydroxyethylrutosides and others) as a single treatment. n/a (n/a) Methods, limits and funding Outcomes: Expert agreement (70% threshold) on use of venoactive nutraceuticals Limitations: Expert opinion from a small national group, not trial evidence. Only the abstract was read. Funding and conflicts: Not stated in the abstract Read: abstract
Bässler 2003 Bioavailability of beta-aescin from horse chestnut seed extract: comparative clinical studies of two Galenic formulations. Adv Ther · PMID 14964349 · DOI	Controlled trial	36 Healthy volunteers (two crossover studies of 18 each)	HCSE: non-retarded versus retarded (slow-release) formulation seed Steady-state dosing · vs The other formulation	Bioequivalence was established: test-to-reference AUC ratio 1.06 (90% CI 0.99 to 1.13) in study 1; 1.07 (0.96 to 1.19) for AUC and 1.05 (0.90 to 1.21) for Cmax in study 2. Absorption was lower at night than in the daytime. Both well tolerated. AUC ratio 1.06 and 1.07; Cmax ratio 1.05 (90% CI as listed) Methods, limits and funding Outcomes: Serum beta-aescin levels (AUC, Cmax) Limitations: Healthy volunteers, not patients. Company authors. Only the abstract was read. Funding and conflicts: Industry-linked: first-listed author affiliation is Steigerwald Arzneimittelwerk GmbH (maker of the product) Read: abstract
Calabrese 1993 Report of the results of a double-blind, randomized, single-dose trial of a topical 2% escin gel versus placebo in the acute treatment of experimentally-induced hematoma in volunteers. Planta Med · PMID 8255928 · DOI	Controlled trial	Healthy volunteers with an experimentally induced bruise (hematoma)	2% escin gel versus placebo gel, single dose seed 2% gel, one application Single dose · vs Placebo gel	The abstract says 2% escin gel reduced tenderness to pressure on the induced bruise compared with placebo. Numbers not given in the abstract (Not given) Methods, limits and funding Outcomes: Tenderness to pressure on the induced bruise Limitations: The abstract is only a few lines, with no sample size or numbers. A model bruise in healthy volunteers, not a clinical injury. Only the abstract was read. Funding and conflicts: Not stated in the abstract Read: abstract
Chen 2019 Escin suppresses HMGB1-induced overexpression of aquaporin-1 and increased permeability in endothelial cells. FEBS Open Bio · PMID 30972964 · DOI	Laboratory research in-vitro	Cultured endothelial (vessel lining) cells	Escin seed Lab doses Lab · vs Untreated cells	Escin reduced the leakiness of endothelial cells caused by the inflammatory protein HMGB1 and lowered the water-channel protein AQP1. n/a (n/a) Methods, limits and funding Outcomes: Vessel-lining cell leakiness Limitations: Cell experiments only. Only the abstract was read. Funding and conflicts: No competing interests declared Read: abstract
Comaish 1980 Contact dermatitis to extract of horse chestnut (esculin). Contact Dermatitis · PMID 7398276 · DOI	Case report	A case of contact dermatitis to horse chestnut extract (esculin)	Topical horse chestnut extract (esculin)	The title reports contact dermatitis to an extract of horse chestnut (esculin). The record has no abstract. n/a (n/a) Methods, limits and funding Outcomes: Skin reaction Limitations: 1980 report with no abstract: only the title was read. Funding and conflicts: Not stated Read: summary-only
Cosi 2025 Allergic reactions to horse chestnut seeds are caused by mugwort pollen Art v 1-sensitization and represent a novel type of defensin-related allergy syndrome. Allergy · PMID 39314061 · DOI	Other	Report of allergy to horse chestnut seeds linked to mugwort pollen sensitisation	Horse chestnut seeds seed	The title states that allergic reactions to horse chestnut seeds are caused by sensitisation to the mugwort pollen protein Art v 1 and represent a novel type of defensin-related allergy syndrome. The record has no abstract. n/a (n/a) Methods, limits and funding Outcomes: Allergic reactions Limitations: A letter with no abstract on PubMed: only the title and record details were read, so no numbers or details are given here. Funding and conflicts: Authors declare no conflict of interest Read: summary-only
Costa Santos 2021 Drug-induced Liver Injury Due to a Horse Chestnut Dietary Supplement. Eur J Case Rep Intern Med · PMID 33869100 · DOI	Case report	1 A 70-year-old man (Portugal)	Horse chestnut dietary supplement	The authors describe a case of idiosyncratic (unpredictable) liver injury attributed to a horse chestnut supplement. They write that clinically significant liver injury has been very rarely linked to it. n/a (n/a) Methods, limits and funding Outcomes: Liver injury Limitations: Single case; the abstract gives no liver test numbers, product details, dose or how causality was judged. Only the abstract was read. Funding and conflicts: Conflicts of interest: none declared Read: abstract
Diehm 1992 Medical edema protection--clinical benefit in patients with chronic deep vein incompetence. A placebo controlled double blind study. Vasa · PMID 1621440	Controlled trial	40 Patients with venous edema from chronic deep vein incompetence	HCSE seed · vs Placebo	Edema-reducing effect of HCSE versus placebo was statistically significant. Leg circumference and vein pressure measures leaned the same way. Well tolerated. Numbers not given in the abstract (Not given in the abstract) Methods, limits and funding Outcomes: Leg volume by water-displacement-type plethysmography (hydroplethysmography), also under provoked swelling; leg circumference; vein pressure measures Limitations: Small (40 people). Dose and duration not in the abstract. Only the abstract was read. Funding and conflicts: Not stated in the abstract Read: abstract
Diehm 1996 Comparison of leg compression stocking and oral horse-chestnut seed extract therapy in patients with chronic venous insufficiency. Lancet · PMID 8569363 · DOI	Controlled trial	240 Adults with chronic venous insufficiency and leg swelling	Dried HCSE (50 mg aescin) twice daily seed 50 mg aescin twice daily 12 weeks · vs Class II compression stockings; placebo	Lower leg volume fell by 43.8 mL with HCSE (n=95) and 46.7 mL with compression (n=99) but rose 9.8 mL with placebo (n=46). Both beat placebo and were shown to be equivalent to each other in the study design. No serious treatment-related events. HCSE -43.8 mL; compression -46.7 mL; placebo +9.8 mL (intention-to-treat) (HCSE 21.1 to 66.4; compression 30.4 to 63.0; placebo -40.0 to 20.4 (as printed in the abstract)) Methods, limits and funding Outcomes: Lower leg volume (swelling) of the more affected leg Limitations: Partially blinded (stockings cannot be blinded). The authors note that in this design compression could not be proven as the standard for swelling reduction. 12 weeks only. Only the abstract was read. Funding and conflicts: Not stated in the abstract Read: abstract
Fang 2010 Escin improves sperm quality in male patients with varicocele-associated infertility. Phytomedicine · PMID 19682880 · DOI	Controlled trial	219 Men with varicocele-associated infertility (China)	Escin taken by mouth seed 60 mg a day (30 mg every 12 h) 2 months · vs Control group and a surgery group	Sperm density improved in 57.5% on escin versus 38.5% in controls (P<0.05); surgery 68.8%. Motility improvement with escin (55.7%) was not significantly different from control (46.2%); surgery (77.1%) was. Few mild side effects, mostly gone when taken after meals. Density improvement 57.5% vs 38.5% vs 68.8% (surgery) (Not given) Methods, limits and funding Outcomes: Sperm density and motility, spermatic vein diameter Limitations: Not placebo-controlled; the control group is not described in the abstract. Only one study. Pregnancy rates not reported in the abstract. Only the abstract was read. Funding and conflicts: Not stated in the abstract Read: abstract
Gallelli 2019 Escin: a review of its anti-edematous, anti-inflammatory, and venotonic properties. Drug Des Devel Ther · PMID 31631970 · DOI	Review	Narrative review of lab and clinical data on escin	Escin (from horse chestnut seed) seed	Reports that escin reduces vessel leakiness in inflamed tissue in animal models, tightens isolated human saphenous veins in vitro, and that oral escin and the gel have shown efficacy in bruising injuries and CVI and are well tolerated. n/a (n/a) Methods, limits and funding Outcomes: Anti-edema, anti-inflammatory and venotonic properties Limitations: Narrative review, not a systematic one. The author reports consultancy and speaker fees from several drug companies. Only the abstract was read. Funding and conflicts: Author reports fees from AstraZeneca, Boehringer Ingelheim, GlaxoSmithKline, Menarini, Pfizer, Mylan, Meda and Zambon Read: abstract
Gwozdzinski 2025 The Effect of Escin on the Plasma Membrane of Human Red Blood Cells. Int J Mol Sci · PMID 41009489 · DOI	Laboratory research in-vitro	Human red blood cells in the lab	Escin seed 15 to 60 microgram/mL Lab · vs Untreated cells	Low concentrations of escin (15 to 60 microgram/mL) broke red blood cells and made the cell membrane more fluid; the authors say the main target is the lipid part of the membrane. n/a (n/a) Methods, limits and funding Outcomes: Red cell breakdown (hemolysis), membrane fluidity Limitations: Lab concentrations may not match blood levels after oral dosing. Only the abstract was read. Funding and conflicts: No competing interests declared Read: abstract
Hu 2016 Aescin-based topical formulation to prevent foot wounds and ulcerations in diabetic microangiopathy. Eur Rev Med Pharmacol Sci · PMID 27831638	Observational	63 Patients with moderate diabetic microangiopathy (registry, not randomised)	Aescin-based cream plus standard foot care versus standard care alone seed Topical cream 8 weeks · vs Standard management	Both groups improved; the aescin cream plus standard care improved more than standard care alone. Numbers not given in the abstract (Not given) Methods, limits and funding Outcomes: Skin blood flow and oxygen measures; foot skin condition Limitations: Registry with self-chosen treatment (not randomised), 63 people, 8 weeks, a branded formulation. Only the abstract was read. Funding and conflicts: Not stated in the abstract; not verified Read: abstract
Huang 2014 Effects of aescin on cytochrome P450 enzymes in rats. J Ethnopharmacol · PMID 24252494 · DOI	Animal research animal	Rats	Aescin, injected into a vein, with probe drugs by mouth seed Lab doses Single or multiple doses · vs Untreated rats	Aescin raised CYP1A2 activity and lowered CYP2C9 and CYP3A4 activity in rats; no effect on CYP2E1. The authors advise caution when aescin is given with drugs handled by CYP1A2, 2C9 or 3A4. n/a (n/a) Methods, limits and funding Outcomes: Activity of liver drug-handling enzymes (CYP1A2, 2C9, 2E1, 3A4) Limitations: Rat study with an intravenous dose; may not apply to people taking oral seed extract. Only the abstract was read. Funding and conflicts: Not stated in the abstract Read: abstract
Isola 2019 Efficacy of a drug composed of herbal extracts on postoperative discomfort after surgical removal of impacted mandibular third molar: a randomized, triple-blind, controlled clinical trial. Clin Oral Investig · PMID 30311061 · DOI	Controlled trial	82 Adults after surgical removal of an impacted lower third molar	Herbal combination (baicalin 190 mg, bromelain 50 mg, escin 30 mg) versus ibuprofen versus placebo seed Escin 30 mg inside the combination, twice a day 5 days · vs Placebo and ibuprofen	The combination reduced pain at 12 h, 24 h and 48 h compared with placebo and ibuprofen. Swelling and jaw stiffness (trismus) reduction were similar between groups. Pain lower at 12 h (p<0.001), 24 h (p=0.010) and 48 h (p=0.048) (Not given) Methods, limits and funding Outcomes: Pain (VAS), mouth opening, facial swelling Limitations: Escin is one of three ingredients, so the effect cannot be credited to escin. Swelling did not differ. Only the abstract was read. Funding and conflicts: Not stated in the abstract Read: abstract
Jaspersen-Schib 1996 [Serious plant poisonings in Switzerland 1966-1994. Case analysis from the Swiss Toxicology Information Center]. Schweiz Med Wochenschr · PMID 8711457	Case series	24950 Severe plant poisonings reported to the Swiss Toxicology Information Center, 1966 to 1994	Contact with or eating toxic plants, including Aesculus hippocastanum	Of 24,950 contacts, 99.4% had unknown, no or only minor symptoms. Among 152 severe cases, Aesculus hippocastanum accounted for 3 (allergy in 3, anaphylactic shock in 2). Aesculus hippocastanum: 3 severe cases of 152 (n/a) Methods, limits and funding Outcomes: Severity and type of poisoning by plant Limitations: Reports to a poison centre, not a rate; the abstract does not say which plant part or product. Article in German; only the abstract was read. Funding and conflicts: Not stated Read: abstract
Koch 2002 Comparative study of Venostasin and Pycnogenol in chronic venous insufficiency. Phytother Res · PMID 11933130 · DOI	Clinical trial	40 Patients with diagnosed CVI (open, controlled comparison)	Venostasin (HCSE) versus Pycnogenol (French maritime pine bark extract) seed HCSE 600 mg a day; Pycnogenol 360 mg a day 4 weeks · vs Pycnogenol (no placebo)	Pycnogenol significantly reduced leg circumference and improved symptoms. HCSE only moderately and non-significantly reduced circumference and marginally improved symptoms. HCSE did not change blood lipids. Both were well tolerated. Not given as numbers in the abstract (Not given) Methods, limits and funding Outcomes: Lower leg circumference, symptom scores, LDL and HDL cholesterol Limitations: Open (not blinded), no placebo, only 40 people, 4 weeks. The result for HCSE here is weaker than in the placebo-controlled trials. Only the abstract was read. Funding and conflicts: Not stated in the abstract Read: abstract
Kuznetsov 2025 [The possibility of using local remedies to reduce the frequency of the 'string' symptom after radiofrequency obliteration of the trunk of the large saphenous vein]. Angiol Sosud Khir · PMID 41805617 · DOI	Controlled trial	180 180 women with varicose veins after radiofrequency ablation of the great saphenous vein (Russian study)	Topical gel with escin, heparin and essential phospholipids; or topical heparin; or no extra treatment seed Applied twice a day 2 weeks · vs Heparin gel; no extra treatment	Edema fell in 91.7% with the escin/heparin/phospholipid gel versus 72.7% (no extra treatment) and 76.9% (heparin) in grade 3 disease (p<0.05). The "string" symptom was reduced with the combination gel. Edema decrease 91.7% versus 72.7% and 76.9% (Not given) Methods, limits and funding Outcomes: Edema, skin changes, ulcers, and the "string" sensation after vein ablation Limitations: Open (not blinded) study, combination gel (escin, heparin and phospholipids), translated from Russian. Only the abstract was read. Funding and conflicts: Conflict of interest: none declared Read: abstract
Leach 2006 Clinical efficacy of horsechestnut seed extract in the treatment of venous ulceration. J Wound Care · PMID 16620045 · DOI	Controlled trial	54 Adults with venous leg ulcers (community nursing service, South Australia)	Oral horse chestnut seed extract seed 12 weeks · vs Placebo	No significant difference in number of healed ulcers or in wound area, depth, volume, pain or exudate. There was a small significant effect on the percentage of wound slough over time (p=0.045) and on dressing changes at week 12 (p=0.009). The authors say the trial was underpowered. Healing not different between groups; slough p=0.045; dressing changes p=0.009 (Not given) Methods, limits and funding Outcomes: Ulcers healed, wound area, depth, volume, pain, exudate, wound slough, dressing changes Limitations: Small (27 per group); too small to detect modest effects; many outcomes tested, so the two positive findings may be chance. Only the abstract was read. Funding and conflicts: Not stated in the abstract Read: abstract
LiverTox (NIDDK) 2012 Horse Chestnut. · PMID 31643542	Reference database	LiverTox: drug-induced liver injury database (NIDDK)	Horse chestnut (leaves or seeds) seed+leaf	Horse chestnut is described as an herb used for venous insufficiency, ankle swelling and leg cramps, and as implicated in rare instances of clinically apparent liver injury. n/a (n/a) Methods, limits and funding Outcomes: Liver injury Limitations: Only the PubMed summary of the LiverTox entry was read; the full entry (likelihood score, case counts) could not be opened because the site showed a browser check. Funding and conflicts: NIH/NIDDK Read: abstract
Ottillinger 2001 Rational therapy of chronic venous insufficiency--chances and limits of the therapeutic use of horse-chestnut seeds extract. BMC Cardiovasc Disord · PMID 11747472 · DOI	Controlled trial	Two studies in early (grade I) and advanced (grade II and IIIa) CVI; one already published	HCSE compared with compression therapy and placebo seed · vs Compression therapy; placebo	In early CVI (grade I) HCSE and compression were both better than placebo and equivalent to each other. In advanced CVI (grade II and IIIa), compression beat placebo but HCSE did not; HCSE did better in grade II than in grade IIIa. Numbers not given in the abstract (Not given) Methods, limits and funding Outcomes: Lower leg volume (edema) Limitations: Report of two studies (one previously published), sample sizes not in the abstract. The conclusions lean on a lab model of vein-wall gaps. The authors argue for starting drug treatment early. Only the abstract was read. Funding and conflicts: Not stated in the abstract. Corresponding author e-mail is a company domain (vicron.net); no funding statement was read. Read: abstract
Owczarek 2019 A validated (1)H qNMR method for direct and simultaneous quantification of esculin, fraxin and (-)-epicatechin in Hippocastani cortex. Talanta · PMID 30348388 · DOI	Other n/a	Commercial horse chestnut bark samples and bark extracts (Poland)	Horse chestnut bark and dry bark extracts bark	In commercial bark samples esculin ranged from 25.89 to 38.94 mg/g dry weight, fraxin 12.58 to 17.13 mg/g and epicatechin 10.42 to 13.96 mg/g. The authors say the large variation between commercial samples shows a need for quality control. Esculin 25.89 to 38.94 mg/g dry weight in bark (n/a) Methods, limits and funding Outcomes: Content of esculin, fraxin and epicatechin Limitations: Measures a lab method on bark; no human outcomes. Only the abstract was read. Funding and conflicts: Not stated Read: abstract
Pabst 2001 Efficacy and tolerability of escin/diethylamine salicylate combination gels in patients with blunt injuries of the extremities. Int J Sports Med · PMID 11531036 · DOI	Controlled trial	126 People with blunt injuries of the limbs from sport	Three escin/diethylamine salicylate gels (Reparil gels) versus placebo gel seed Topical, as per product Pain measured up to 24 hours · vs Placebo gel	All three active gels were significantly better than placebo (p=0.0004 each); pain fell faster. No adverse events in 126 people. Mean tenderness AUC differed between groups (Kruskal-Wallis p=0.0001) (Not given) Methods, limits and funding Outcomes: Pain on pressure over 6 hours; pain scale Limitations: Combination products (salicylate included), short period, single centre. Only the abstract was read. Funding and conflicts: Funding not stated in the abstract; the products are Reparil gels and co-authors Wetzel and Bulitta also wrote the Madaus AG trial above Read: abstract
Pan 2026 Sodium aescinate induces renal cell ferroptosis through the ATF4/CTH/SQOR axis. Biochem Pharmacol · PMID 41759595 · DOI	Animal research in-vitro	Kidney cells in the lab	Sodium aescinate (SA) from Aesculus wilsonii seeds (Chinese species) seed Lab doses Lab · vs Untreated cells	The authors say sodium aescinate has been linked to severe kidney injury in clinical use, and show it causes ferroptosis-mediated kidney cell injury in the lab through the ATF4/CTH/SQOR pathway. n/a (n/a) Methods, limits and funding Outcomes: Kidney cell ferroptosis pathway Limitations: Cell work on a different species (Aesculus wilsonii) and an injectable salt; not proof of risk with oral European seed extract. Only the abstract was read. Funding and conflicts: Competing interests: none declared Read: abstract
Pittler 2012 Horse chestnut seed extract for chronic venous insufficiency. Cochrane Database Syst Rev · PMID 23152216 · DOI	Systematic review	People with chronic venous insufficiency (CVI) in randomised trials of oral horse chestnut seed extract (HCSE) alone versus placebo or a reference treatment	Horse chestnut seed extract (HCSE), single-herb oral products seed Various (not stated in the abstract) Various (not stated in the abstract) · vs Placebo or reference therapy	Overall, CVI signs and symptoms improved with HCSE compared with placebo. Leg pain: 6 of 7 placebo-controlled trials reported a significant drop versus placebo, 1 versus baseline. Leg volume: 6 trials (n=502) favoured HCSE. One trial suggested HCSE may be as effective as compression stockings. Adverse events were usually mild and infrequent. Leg pain: weighted mean difference 42.4 mm on a 100 mm scale (one trial). Leg volume: weighted mean difference 32.1 mL in favour of HCSE (6 trials, n=502). (Pain 34.9 to 49.9 mm; volume 13.49 to 50.72 mL) Methods, limits and funding Outcomes: Leg pain, leg volume, other CVI signs and symptoms, adverse events Limitations: Reviewers say larger definitive trials are needed. Search ended June 2012. Only the abstract was read, so the number of trials, their quality scores and any GRADE rating are not known here. The pain figure comes from a single trial. Funding and conflicts: Cochrane review; conflict of interest statement: none known Read: abstract
Rehn 1996 Comparative clinical efficacy and tolerability of oxerutins and horse chestnut extract in patients with chronic venous insufficiency. Arzneimittelforschung · PMID 8737631	Controlled trial	137 Postmenopausal women with CVI stage II (137 finished)	Horse chestnut extract (HCE) versus oxerutins (hydroxyethylrutosides) seed HCE 600 mg a day; oxerutins 1000 mg a day (or 1000 mg then 500 mg) About 4 weeks then up to 12 weeks, then 6 weeks follow-up · vs Oxerutins (and a 1-week placebo run-in)	Oxerutins 1000 mg a day were found equivalent or better at reducing leg volume than HCE. Leg volume change (area measure) was -5273 mL x days with oxerutins, -3004 with HCE. Oxerutins -5273 +/- 11418 mL.d; HCE -3004 +/- 7429 mL.d (Not given) Methods, limits and funding Outcomes: Leg volume reduction (main confirmatory outcome) Limitations: Not placebo-controlled in the comparison phase. The aim was to test the oxerutin dose plan. Sponsor is the maker of oxerutins (Zyma). Only the abstract was read. Funding and conflicts: Industry-linked: author affiliation Zyma GmbH, a company that sells the oxerutin comparator Read: abstract
Rothkopf 1977 Animal experiments on the question of the renal toleration of the horse chestnut saponin aescin. Arzneimittelforschung · PMID 301389	Animal research animal	Rats and an isolated frog kidney model	Aescin and sodium aescinate (by injection) seed Injected doses in the rat tests (for example 0.35 mg/kg and 2.2 mg/kg into a vein) Short-term · vs Untreated damaged-kidney controls	Aescin had no effect on kidney damage caused by three kidney poisons in rats. In the frog kidney, aescin increased sodium and glucose in the urine at low concentrations and urine production stopped at 5 mg/l; adding albumin removed the effect. n/a (n/a) Methods, limits and funding Outcomes: Kidney clearance, mortality in rats with damaged kidneys, tubular transport in frog kidney Limitations: Animal and frog kidney work from 1977 with injected sodium aescinate; does not describe a human kidney problem from oral seed extract. Only the abstract was read. Funding and conflicts: Not stated Read: abstract
Sanmee 2024 The efficacy of Aescin combined with MPFF for early control of bleeding from acute hemorrhoids, A randomized controlled trial. Asian J Surg · PMID 39153932 · DOI	Controlled trial	120 Adults with grade 1 or 2 acute hemorrhoids (Chiang Mai University, Thailand)	Aescin plus micronized purified flavonoid fraction (MPFF), versus MPFF alone seed · vs MPFF alone	Aescin plus MPFF stopped bleeding sooner (2 days versus 4 days) and resolved the mass effect sooner (4 versus 5 days) than MPFF alone; treatment failure was lower with the combination. Bleeding stopped in 2 days versus 4; mass effect resolved in 4 days versus 5 (Not given) Methods, limits and funding Outcomes: Time to bleeding stopping and to resolution of mass effect; treatment failure; satisfaction Limitations: The abstract says 120 patients were randomised "to each group", so the total may be larger; the number is reported as written. Tests the add-on of aescin to another venoactive drug, not aescin alone versus placebo. Blinding not stated in the abstract. Only the abstract was read. Funding and conflicts: Not stated in the abstract Read: abstract
Sharipov 2021 Hypoglycemic and Anti-Inflammatory Effects of Triterpene Glycoside Fractions from Aeculus hippocastanum Seeds. Molecules · PMID 34206308 · DOI	Animal research animal	Rodents (in vivo tests)	Fractions of triterpene saponins from Aesculus hippocastanum seeds grown in Uzbekistan seed Lab doses Lab · vs Controls	Different saponin fractions showed the highest (SF-1, SF-2) and lowest (SF-5, SF-8) blood sugar-lowering and anti-inflammatory effects in the animal tests. n/a (n/a) Methods, limits and funding Outcomes: Blood sugar-lowering and anti-inflammatory activity Limitations: Animal work with isolated saponin fractions; the abstract does not say which animal or give numbers. No human data. Only the abstract was read. Funding and conflicts: Competing interests: none declared Read: abstract
Siebert 2002 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 · PMID 12518108	Meta-analysis	People with CVI: 13 randomised trials (1,051 people) and 3 observational studies (10,725 people)	HCSE (oral) seed Various Various · vs Placebo (RCTs); none (observational)	HCSE improved symptoms in the randomised trials. No severe adverse events were reported and mild events were not significantly increased. Not enough evidence for effects on leg fatigue/heaviness or calf cramps. Observational studies showed gains in pain, edema and leg fatigue/heaviness. Leg volume reduced by 46.4 mL versus placebo; leg pain improvement 4.1-fold more likely; edema improvement 1.5-fold more likely; itching 1.7-fold more likely (Leg volume 11.3 to 81.4 mL; pain 0.98 to 16.8; edema 1.2 to 1.9; itching 0.01 to 3.0) Methods, limits and funding Outcomes: Leg volume, ankle and calf circumference, edema, pain, tension, leg fatigue/heaviness, cramps, itching, adverse events Limitations: The pain interval nearly includes no effect and the itching interval is very wide. Observational studies cannot prove cause. Long-term effects not tested. Only the abstract was read. Funding and conflicts: Not stated in the abstract Read: abstract
Sun 2023 Characterization of the horse chestnut genome reveals the evolution of aescin and aesculin biosynthesis. Nat Commun · PMID 37833361 · DOI	Other n/a	Genome study of Aesculus chinensis (Chinese horse chestnut), not A. hippocastanum	Aesculus chinensis plant genes seed	The study found gene groups that make aescin in the seed and genes that make the coumarin glycoside aesculin (esculin). n/a (n/a) Methods, limits and funding Outcomes: Genes that make aescin and aesculin Limitations: A different species from the European horse chestnut; shows both compound families are made by the plant. Only the abstract was read. Funding and conflicts: No competing interests declared Read: abstract
Suter 2006 Treatment of patients with venous insufficiency with fresh plant horse chestnut seed extract: a review of 5 clinical studies. Adv Ther · PMID 16644618 · DOI	Systematic review	Review of 5 clinical studies of one fresh-plant HCSE product (Aesculaforce) in CVI and varicose veins	Fresh-plant HCSE (tincture, tablets, gel) seed Various Various · vs Various	The review says the studies showed reduced lower-leg edema and relief of pain, heaviness and itching, and that the product was safe and well tolerated. Numbers not given in the abstract (Not given) Methods, limits and funding Outcomes: Lower leg edema, leg pain, heaviness, itching Limitations: Narrative review of one manufacturer-type product; not a Cochrane-style review. Only the abstract was read. Funding and conflicts: Authors Suter A, Bommer S, Rechner J; funding not stated in the abstract and company links not verified Read: abstract
Vipudhamorn 2026 Efficacy of escin combined with micronized purified flavonoid fraction in controlling bleeding and preventing recurrence of acute internal hemorrhoids: a randomized controlled trial. Ann Coloproctol · PMID 42392851 · DOI	Controlled trial	108 Adults with grade 1 or 2 acutely bleeding internal hemorrhoids who achieved hemostasis	Escin plus MPFF, versus placebo plus MPFF seed Escin 120 mg a day (as stated) 7 days of MPFF 3,000 mg a day then 2 months of MPFF 1,000 mg a day, with escin or placebo · vs Matched placebo plus MPFF	Recurrence was 0% versus 7.84% at 1 month and 7.02% versus 23.52% at 3 months (escin versus placebo). Median time to bleeding stopping 2 days versus 4 days (P<0.001). Symptom scores improved more with escin. No adverse events in either group. Hazard ratio reported as 3.95 (P=0.009) for reduced recurrence with the combination (Not given in the abstract) Methods, limits and funding Outcomes: Recurrence within 90 days (proctoscopy-confirmed), time to hemostasis, hemorrhoid symptom scale, safety Limitations: Single centre, add-on design (MPFF in both arms), only grade 1 to 2, 90 days. The hazard ratio is quoted as printed in the abstract. Only the abstract was read. Funding and conflicts: Conflict of interest: none reported. Registered on ClinicalTrials.gov NCT06748014. Registration: ClinicalTrials.gov NCT06748014 Read: abstract
Voigt 1978 [Acute posttraumatic renal failure following therapy with antibiotics and beta-aescin (author's transl)]. Anaesthesist · PMID 637297	Case report	1 One patient after injury (Germany)	Gentamicin plus beta-aescin seed	A case of acute kidney failure after treatment with the antibiotic gentamicin and beta-aescin is reported; the authors discuss which agent caused it. Kidney function was restored using dialysis. n/a (n/a) Methods, limits and funding Outcomes: Acute kidney failure Limitations: 1978 case with two drugs at once, so cause cannot be assigned; German-language article; only the abstract was read. Funding and conflicts: Not stated Read: abstract
Wang 2023 Comparison of Semen Aesculi species from different geographical origins and horse chestnut based on metabolomics and chemometrics analysis. Phytochem Anal · PMID 36843182 · DOI	Other n/a	Chemical comparison of European horse chestnut seed and three official Chinese Semen Aesculi species	Semen Aesculi (Chinese species) and A. hippocastanum seeds seed	The three Chinese Semen Aesculi species separated clearly from each other, while European horse chestnut and Aesculus chinensis looked chemically similar. n/a (n/a) Methods, limits and funding Outcomes: Chemical profile (44 compounds identified) Limitations: Chemistry only, no clinical outcomes; shows that species identity matters for quality control. Only the abstract was read. Funding and conflicts: Not stated Read: abstract
Wetzel 2002 Escin/diethylammonium salicylate/heparin combination gels for the topical treatment of acute impact injuries: a randomised, double blind, placebo controlled, multicentre study. Br J Sports Med · PMID 12055112 · DOI	Controlled trial	158 Athletes (soccer, handball, karate) within 2 hours of a strain, sprain or contusion	Topical gel with escin (1% or 2%), diethylammonium salicylate 5% and heparin 5000 IU seed 1% or 2% escin in a combination gel, applied three times in 8 hours 24 hours · vs Placebo gel	Both escin combination gels beat placebo on the main measure (p=0.0001 and 0.0002); pain resolved sooner; gels were well tolerated. Treatment effect 5.7 kp h/cm2 (1% escin) and 5.9 kp h/cm2 (2% escin) versus placebo (1% escin 2.9 to 8.5; 2% escin 2.9 to 8.8) Methods, limits and funding Outcomes: Pain on pressure (tenderness) over 6 hours Limitations: The gel also contains a salicylate and heparin, so the effect cannot be credited to escin alone; no escin-only arm. Short follow-up. Only the abstract was read. Funding and conflicts: Industry-linked: first-listed affiliation is Madaus AG (maker of the gels) Read: abstract
Wu 2010 Simultaneous analysis of isomers of escin saponins in human plasma by liquid chromatography-tandem mass spectrometry: application to a pharmacokinetic study after oral administration. J Chromatogr B Analyt Technol Biomed Life Sci · PMID 20185376 · DOI	Clinical trial	Healthy volunteers after oral sodium aescinate tablets (60 mg escin saponins); mainly a lab-method paper	Sodium aescinate tablets seed 60 mg escin saponins Single oral dose	The method detects very low levels (lower limit 33 pg/mL) of four escin isomers in human plasma and was used in a pharmacokinetic study of volunteers. n/a (n/a) Methods, limits and funding Outcomes: Plasma levels of four escin isomers (method development) Limitations: The abstract gives no results of the volunteer study (number of people, peak levels). Only the abstract was read. Funding and conflicts: Not stated in the abstract Read: abstract
Wu 2014 Comparative pharmacokinetics and the bioavailability of escin Ib and isoescin Ib following the administration of escin, pure escin Ib and isoescin Ib in rats. J Ethnopharmacol · PMID 24334163 · DOI	Animal research animal	Wistar rats (n=6 per group)	Sodium escinate, pure escin Ib and isoescin Ib seed Intravenous 0.5 mg/kg; oral 4 mg/kg of pure isomers Single doses · vs Each compound alone	Oral absorption of escin Ib and isoescin Ib was very poor: bioavailability below 2% for both. The two isomers convert into each other in the body. Oral bioavailability F below 2% (n/a) Methods, limits and funding Outcomes: Blood levels of escin Ib and isoescin Ib; oral bioavailability Limitations: Rat data; human oral bioavailability not given. Only the abstract was read. Funding and conflicts: Not stated in the abstract Read: abstract
Xie 2009 Pilot postoperative ileus study of escin in cancer patients after colorectal surgery. World J Surg · PMID 19052813 · DOI	Controlled trial	72 Colorectal cancer patients after surgery (China), pilot study	Escin given by intravenous drip (sodium escinate-type injection) seed 5, 15 or 25 mg once a day in 500 mL dextrose through a vein Up to 7 days · vs Placebo	Escin 15 mg and 25 mg shortened time to passing gas by 10.75 h (p=0.036) and 17.31 h (p=0.022) versus placebo. Bowel movement returned 23.44 h (p=0.035) and 23.83 h (p=0.019) sooner. Bowel sounds were not significantly different. 5 mg did not differ from placebo. Passing gas: -10.75 h (15 mg), -17.31 h (25 mg); bowel movement: -23.44 h, -23.83 h (Not given) Methods, limits and funding Outcomes: Time to passing gas, bowel sounds and bowel movements Limitations: Pilot, 18 per group, intravenous drug not the oral supplement. Sodium escinate injection is a prescription product in China and is not the same as oral seed extract. Only the abstract was read. Funding and conflicts: Not stated in the abstract Read: abstract
Zając 2014 [Intoxication by powdered seeds of horse chestnut (Aesculus hippocastanum) used nasally as snuff - a case report]. Przegl Lek · PMID 25632792	Case report	1 A 15-year-old girl (Poland)	Powdered horse chestnut seeds used as snuff seed Single use	Vomiting, breathlessness, burning in the nose and throat, and fainting after snuffing the powder; tests were normal; she went home after 2 days. The authors name aescin as mainly responsible and say frequent symptoms of aescin poisoning are stomach and gut irritation and allergic reactions. n/a (n/a) Methods, limits and funding Outcomes: Symptoms after snuffing Limitations: One case; Polish-language article; only the abstract was read. Funding and conflicts: Not stated Read: abstract
Zheng 2025 Sodium aescinate induces hepatotoxicity through apoptosis and ferroptosis by inhibiting the Nrf2/CTH pathway. J Ethnopharmacol · PMID 40064321 · DOI	Animal research animal	Mouse liver cells and mice	Sodium aescinate (SA) from Aesculus wilsonii seeds, injected form seed Lab doses Lab · vs Untreated	Sodium aescinate caused liver cell death through ferroptosis and apoptosis by suppressing the Nrf2/CTH pathway in mice and mouse liver cells. n/a (n/a) Methods, limits and funding Outcomes: Liver cell death markers Limitations: Mouse and cell work with a Chinese species and an injectable salt; not oral standardised seed extract. Only the abstract was read. Funding and conflicts: Not stated in the abstract Read: abstract
Zhu 2024 Nrf2/FSP1/CoQ10 axis-mediated ferroptosis is involved in sodium aescinate-induced nephrotoxicity. Arch Biochem Biophys · PMID 39033970 · DOI	Animal research animal	Cultured rat kidney tubule cells and mice	Sodium aescinate (SA, from horse chestnut-type seeds), injected form seed Lab doses Lab · vs Untreated cells/mice	Sodium aescinate reduced kidney cell survival and triggered a form of cell death called ferroptosis through the Nrf2/FSP1/CoQ10 pathway. The authors state that SA-related adverse events, especially kidney impairment, have increased in clinical use. n/a (n/a) Methods, limits and funding Outcomes: Kidney cell survival, ferroptosis markers Limitations: Lab and mouse work on sodium aescinate (a prescription injection in China), not on oral standardised seed extract. Only the abstract was read. Funding and conflicts: Competing interests: none declared Read: abstract
s-ema-hmpc-hippocastani-semen EU herbal monograph on Aesculus hippocastanum L., semen (horse-chestnut seed), Final - Revision 1 (EMA/HMPC/628242/2018, adopted 15 January 2020) · Source	Authoritative guidance n/a			Methods, limits and funding Read: full-text
s-gbif-aesculus-hippocastanum GBIF Backbone: Aesculus hippocastanum L. (usageKey 3189815) · Source	Reference database n/a			Methods, limits and funding Read: full-text
s-ncbi-taxonomy-aesculus-hippocastanum NCBI Taxonomy: Aesculus hippocastanum (taxid 43364) · Source	Reference database n/a			Methods, limits and funding Read: full-text
s-nccih-horse-chestnut NIH NCCIH: Horse Chestnut, Usefulness and Safety · Source	Authoritative guidance n/a			Methods, limits and funding Read: full-text
s-pubchem-hippocastanum-compounds PubChem compound records (name lookups): esculin, esculetin, escin, aescin, protoescigenin, fraxin, quercetin, kaempferol, epicatechin, procyanidin B2, warfarin · Source	Reference database n/a			Methods, limits and funding Read: full-text

What we do not know yet

What the evidence supports: modest short-term gains in leg swelling and pain from standardised seed extract in chronic venous insufficiency (moderate certainty).
What is uncertain: most trials are old, small and short; hemorrhoid and bruise results rely on add-on or combination products, often from one research group or maker.
Not known: long-term safety beyond about 12 weeks, safety in pregnancy and children, and exactly how it interacts with blood thinners or diabetes medicines.
The toxic component of raw seed, bark and leaf is not named by NCCIH.

How new research is added

New studies are found by a saved PubMed search and are placed in a review queue. A person reads each one before it changes any evidence rating, safety wording or dose information. New publications never change ratings automatically.

Lab markers

What changed in blood or saliva tests during trials. A changed number is not the same as feeling or being healthier, and we give no "normal ranges".

Other 10

▼

Lower leg volume (mL)

Lowered in trials

The amount of fluid-driven volume in the lower leg, measured with water displacement or plethysmography.

Moderate certainty

Results and what it means

Why it was measured

The most common objective measure of swelling in venous trials.

Statistical vs. clinical meaning

A change of tens of millilitres is statistically significant but of modest size; whether it matters for how people feel is not settled.

Safety implication

None specific.

Study	Result	People	Product
²⁷	Weighted mean difference 32.1 mL less than placebo in 6 trials (n=502)	CVI	HCSE vs placebo
¹¹	HCSE -43.8 mL; compression -46.7 mL; placebo +9.8 mL after 12 weeks	240 adults with CVI	HCSE 50 mg aescin twice daily
³²	46.4 mL less than placebo	CVI, RCTs	HCSE

^{27 11 32}

▼

Leg pain on a 100 mm visual analogue scale

Lowered in trials

A line from 0 (no pain) to 100 mm (worst pain) on which people mark their pain.

Low certainty

Results and what it means

Why it was measured

Pain is the main reason for treatment.

Statistical vs. clinical meaning

The big number comes from one trial; scales are subjective.

Safety implication

None specific.

Study	Result	People	Product
²⁷	Weighted mean difference 42.4 mm (CI 34.9 to 49.9) in one trial; 6 of 7 trials significant versus placebo	CVI	HCSE vs placebo

²⁷

▼

Capillary filtration coefficient

Lowered in trials

How easily fluid leaks out of the smallest vessels in the leg, measured by venous-occlusion plethysmography.

Low certainty

Results and what it means

Why it was measured

A lab measure of the leakiness that causes swelling.

Statistical vs. clinical meaning

A single-dose lab measure in 22 people; does not show symptom relief.

Safety implication

None specific.

Study	Result	People	Product
²	Fell 22% three hours after a single dose versus a slight rise on placebo (P=0.006)	22 patients with CVI, crossover	Two capsules of 50 mg aescin each

↕

Lower leg circumference

Mixed results in trials

Tape-measure size of the calf or ankle.

Low certainty

Results and what it means

Why it was measured

Simple swelling check.

Statistical vs. clinical meaning

Mixed results; one study found little change.

Safety implication

None specific.

Study	Result	People	Product
¹⁰	Circumference leaned the same way as volume but the abstract gives no numbers	40 patients with chronic deep vein incompetence	HCSE
¹⁹	Only moderate, non-significant reduction with HCSE; Pycnogenol reduced it significantly	40 patients, open study	HCSE 600 mg a day, 4 weeks

^{10 19}

●

Healed venous leg ulcers (number)

No clear change in trials

How many ulcers had closed by the end of the trial.

Not enough evidence

Results and what it means

Why it was measured

The key outcome for ulcer treatment.

Statistical vs. clinical meaning

Underpowered trial.

Safety implication

None specific.

Study	Result	People	Product
²¹	No significant difference in the number of healed ulcers versus placebo	54 adults with venous ulcers	Oral HCSE for 12 weeks

²¹

▼

Time until bleeding stops (days)

Lowered in trials

Days from treatment start until bleeding from hemorrhoids stopped.

Low certainty

Results and what it means

Why it was measured

Main short-term outcome in hemorrhoid trials.

Statistical vs. clinical meaning

Faster by about two days; both trials are from one team.

Safety implication

Bleeding that continues needs a doctor.

Study	Result	People	Product
³⁰	Median 2 days with aescin plus MPFF versus 4 days with MPFF alone	Adults with grade 1 or 2 acute hemorrhoids	Aescin plus MPFF versus MPFF
³⁵	Median 2 days versus 4 days (P<0.001)	108 adults who achieved hemostasis	Escin 120 mg a day plus MPFF versus placebo plus MPFF

^{30 35}

▼

Recurrence of hemorrhoid bleeding at 3 months

Lowered in trials

Return of bleeding confirmed by proctoscopy within 90 days.

Low certainty

Results and what it means

Why it was measured

Longer-term control.

Statistical vs. clinical meaning

One trial.

Safety implication

None.

Study	Result	People	Product
³⁵	7.02% with escin versus 23.52% with placebo at 3 months (reported hazard ratio 3.95, P=0.009)	108 adults	Escin plus MPFF versus placebo plus MPFF

³⁵

▲

Pain on pressure (tenderness) over 6 hours

Raised in trials

The pressure applied at the centre of a bruise or injury before the person feels pain.

Low certainty

Results and what it means

Why it was measured

Standard outcome in blunt injury gel trials.

Statistical vs. clinical meaning

Short-term pain on pressure; combination gels.

Safety implication

None.

Study	Result	People	Product
³⁸	Treatment effect 5.7 and 5.9 kp h/cm2 versus placebo (1% and 2% escin combination gels)	158 athletes	Escin/salicylate/heparin gel
²⁵	All three escin combination gels beat placebo (p=0.0004 each)	126 people	Reparil gels

^{38 25}

▼

Time to passing gas after surgery (hours)

Lowered in trials

Hours until first passage of gas after colon surgery.

Very low certainty

Results and what it means

Why it was measured

Sign that gut movement has returned.

Statistical vs. clinical meaning

Pilot trial.

Safety implication

Injected form only.

Study	Result	People	Product
⁴¹	76.78 h (5 mg), 72.06 h (15 mg), 65.50 h (25 mg); 10.75 h and 17.31 h sooner than placebo for the two higher doses	72 colorectal cancer patients	Escin by vein for up to 7 days

⁴¹

▲

Sperm density improvement rate

Raised in trials

Percentage of men whose sperm density improved.

Very low certainty

Results and what it means

Why it was measured

Fertility surrogate.

Statistical vs. clinical meaning

One trial; not pregnancy outcome.

Safety implication

None.

Study	Result	People	Product
¹²	57.5% on escin, 68.8% after surgery, 38.5% in controls	219 men with varicocele-associated infertility	Escin 60 mg a day for 2 months

¹²

Safety

What studies and official sources say about side effects, medicines and who should check first. Each point shows what kind of evidence it comes from.

Main points to know 9

Raw horse chestnut seed, bark, leaf and flower are poisonous: only standardised seed extracts have been studied. NCCIH says the raw seeds, bark, flowers and leaves are unsafe by mouth because they contain a toxic component, and that standardised seed extracts, from which this component has been removed, are likely safe for short-term use (used safely in studies for up to 12 weeks). Esculin (also spelled aesculin), a coumarin-type compound found in the bark and elsewhere in the plant, is often named as the toxic part, but the NCCIH page does not name it and we did not read a source that does, so that link is not verified here. Bark samples in one study held 25.89 to 38.94 mg of esculin per gram. Do not make your own tea, powder or snuff from conkers, bark or leaves. A teenager became unwell (vomiting, breathlessness, burning nose and throat, fainting) after snuffing powdered seeds. Authoritative guidance ^{48 42 24}
Do not treat sudden leg swelling, severe pain, ulcers or skin infection with a supplement. The EU monograph says to see a doctor for inflammation of the skin, thrombophlebitis, hardened tissue under the skin, severe pain, ulcers, sudden swelling of one or both legs, and cardiac or renal insufficiency. Sudden swelling of one leg can be a blood clot. Authoritative guidance ⁴⁵
Kidney problems: ask a doctor first. The EU monograph advises consulting a doctor if you have renal (kidney) insufficiency. A 1978 German case report describes acute kidney failure after gentamicin and beta-aescin together; the cause could not be separated. Lab and mouse studies of sodium aescinate (an injectable form used clinically in China, made from related seed species) report kidney injury and say adverse events including kidney impairment have increased in clinical use. These findings do not show that oral standardised seed extract harms the kidneys, but they are the reason for care. Authoritative guidance ^{45 36 44 26}
Liver: rare injury reported. LiverTox says horse chestnut has been implicated in rare instances of clinically apparent liver injury, and a 2021 case report describes a 70-year-old man with liver injury attributed to a horse chestnut supplement. The EU monograph we read does not mention the liver. Stop and seek care for yellow skin or eyes, dark urine or pale stools. Case report ^{22 9 45}
Bleeding and blood thinners: caution is advised, evidence is weak. A 2000 Italian review lists horse chestnut among herbs said to reinforce warfarin and recommends not using it with blood thinners or antiplatelet drugs, but its abstract gives no case data. Esculin is a coumarin derivative, and warfarin is also a coumarin derivative, but we found no study showing that esculin or horse chestnut thins the blood, so this is a theory only. The EU monograph reports no interactions. Tell your doctor before surgery. Pharmacological theory ^{1 45}
Allergy and skin reactions. The EU monograph contraindicates use if you are hypersensitive to horse chestnut and lists itching and allergic reactions (frequency unknown). A Swiss poison centre analysis lists 3 severe cases with Aesculus hippocastanum, all allergy and 2 with anaphylactic shock. Contact dermatitis to horse chestnut extract (esculin) was reported in 1980, and a 2025 letter links allergy to horse chestnut seeds with mugwort pollen sensitisation (title only read). Authoritative guidance ^{45 18 7 8}
Pregnancy, breastfeeding and young people. The EU says use during pregnancy and breastfeeding is not recommended because safety has not been established, and NCCIH says little is known. The oral use is not recommended under 18; the bruise use is not recommended under 12. Authoritative guidance ^{45 48}
Diabetes medicines: no human data, watch your sugar. We found no human study of horse chestnut with diabetes medicines. A lab study of saponin fractions found blood sugar-lowering effects in animals. In theory it could add to diabetes drugs; check blood sugar and ask your doctor or pharmacist. Pharmacological theory ³¹
Stomach upset, dizziness, headache and itching are the usual side effects. NCCIH and the EU monograph list dizziness or vertigo, digestive upsets, headache and itching; the frequency is not known. The Cochrane review described adverse events as usually mild and infrequent. Systematic review ^{45 48 27}

Side effects 8

Effect	How often	Severity and recovery	Evidence
Stomach and gut complaints (nausea, upset stomach) A trial of escin in men noted mild effects that eased when taken after meals.	Frequency not known (EU monograph)	mild Presumed reversible	Authoritative guidance ^{45 48}
Headache	Frequency not known	mild Presumed reversible	Authoritative guidance ^{45 48}
Dizziness or vertigo	Frequency not known	mild Presumed reversible	Authoritative guidance ^{45 48}
Itching and skin reactions (including from gels) Cutaneous use: itching and redness reported (EU monograph).	Frequency not known	mild to moderate Presumed reversible after stopping	Authoritative guidance ^{45 7}
Allergic reactions including anaphylaxis The abstract does not say which product or plant part.	3 severe cases in a 29-year Swiss poison-centre review (a count, not a rate)	mild to life-threatening Not stated	Case series ^{18 45}
Irritation of nose and throat, vomiting, fainting after snuffing raw seed powder Not a supplement use.	One case	moderate Recovered in 2 days	Case report ⁴²
Acute kidney failure (with gentamicin) Two drugs at once; cause not clear.	One case in 1978	severe Kidney function restored with dialysis	Case report ³⁶
Liver injury	Described as rare (LiverTox); no rate found	moderate to severe Not stated in the abstracts read	Case report ^{22 9}

Liver

LiverTox describes horse chestnut as implicated in rare instances of clinically apparent liver injury, and one 2021 case report describes a 70-year-old man with idiosyncratic (unpredictable) liver injury attributed to a horse chestnut supplement; the abstract gives no test values, product or dose. The EU monograph we read does not mention the liver. Mouse and cell studies of injected sodium aescinate (related Chinese seeds) show liver cell death. This lab work does not tell us about oral supplements in people. The LiverTox likelihood score is not verified. ^{22 9 43 45}

How often. Described as rare; no rate found. Absence of reports is not proof of safety.

Monitoring. No agency monitoring advice was found. Stop and seek care for yellow skin or eyes, dark urine, pale stools or severe itching.

This is a safety connection. It is not evidence that Horse Chestnut supports liver health.

Medicines and supplements 5

With	Why it matters	Importance	Evidence	What to do
Warfarin and other blood thinners (anticoagulants), antiplatelet drugs prescription	Theory: esculin is a coumarin derivative (as is warfarin) but blood thinning by esculin is not shown; one 2000 review lists horse chestnut among herbs that reinforce warfarin.	No case report or trial data are given in the abstract of the review. The EU monograph reports no interactions.	Pharmacological theory Very low certainty ^{1 45}	Do not start without telling your doctor; ask about extra blood tests if you use warfarin.
Diabetes medicines (insulin, metformin, sulfonylureas and others) prescription	Animal work found blood sugar lowering with saponin fractions.	No human data.	Animal research Not enough evidence ³¹	Check blood sugar more often and ask your doctor or pharmacist.
Drugs handled by liver enzymes CYP1A2, CYP2C9 and CYP3A4 prescription	Rats given aescin into a vein: CYP1A2 activity rose, CYP2C9 and CYP3A4 fell.	No human data; the dose was injected, not taken by mouth.	Animal research Not enough evidence ¹⁶	Ask a pharmacist before combining with medicines with narrow safety margins.
Drugs that can harm the kidneys (for example some antibiotics such as gentamicin, and some anti-inflammatory drugs) prescription	One 1978 case of kidney failure involved gentamicin together with beta-aescin.	Cannot separate the two agents.	Case report Very low certainty ^{36 45}	People with kidney disease or on kidney-risk drugs should ask a doctor first.
Other blood-vessel or venous supplements and combination products supplement	Overlapping effects possible; not studied.	No data.	Pharmacological theory Not enough evidence ⁴⁵	Keep a list of what you take and show it to your pharmacist.

Who should check first 9

Situation	Advice	Evidence
Allergy to horse chestnut (or a past reaction)	Do not use. EU contraindication is hypersensitivity.	Authoritative guidance ⁴⁵
Raw seeds, conkers, bark, leaf or flower taken by mouth	Do not use; unsafe by mouth (NCCIH).	Authoritative guidance ⁴⁸
Kidney insufficiency	EU monograph: consult a doctor. Avoid unless a doctor agrees.	Authoritative guidance ⁴⁵
Liver disease or past liver injury from a supplement	Avoid unless a doctor agrees; rare injury reported.	Case report ^{22 9}
Taking warfarin or other blood thinners; planned surgery	Ask a doctor first (theory-based caution).	Pharmacological theory ¹
Pregnancy and breastfeeding	Not recommended; safety not established (EU).	Authoritative guidance ^{45 48}
Under 18 (oral); under 12 (bruise use)	Not recommended.	Authoritative guidance ⁴⁵
Sudden one-sided leg swelling, thrombophlebitis, leg ulcers, severe pain or skin infection	See a doctor instead of self-treating.	Authoritative guidance ⁴⁵
Broken skin, eyes or mucous membranes (for gels)	Do not apply.	Authoritative guidance ⁴⁵

Overdose, product quality and regulators

Summary. Raw horse chestnut seed, bark, leaf and flower are toxic by mouth; standardised seed extract (with the toxic part removed) has low toxicity in the data read. Do not confuse conkers with edible sweet chestnuts.

Animal. The EU monograph says available preclinical data indicate low toxicity after oral administration of the herbal preparation, but adequate tests on reproductive toxicity, genotoxicity and carcinogenicity have not been performed. Injected sodium aescinate (from related Chinese seeds) damaged kidney and liver cells in mouse and cell studies; aescin injected into rats raised or lowered some liver enzymes.

Human doses studied. Standardised extracts were used for up to about 12 weeks in trials (NCCIH: safe in research up to 12 weeks). Details of amounts are not given here; ask a doctor or pharmacist.

High dose or long term signals. No case of overdose has been reported to the EU. Long-term use beyond about 12 weeks is not well studied.

Overdose response. Not reported with standardised extract. The one case found with raw powder was a teenager who snuffed seed powder and recovered in two days.

Genotoxicity. Not tested adequately (EU monograph).

Toxic plant parts. NCCIH: raw seeds, bark, flowers and leaves are unsafe by mouth because of a toxic component. The component is not named on the NCCIH page. Esculin, a coumarin glycoside found in bark (25.89 to 38.94 mg/g in commercial bark samples) and made by the plant, and saponins such as aescin (irritant to mucous membranes in the snuff case) are candidates; this assignment is NOT verified from a primary toxicology source.

We found no survey of contamination (heavy metals, pesticides, microbes) in horse chestnut products. Quality problems that are documented are about identity and content: species differ chemically, and the amount of the key compounds varies between commercial samples.

Species differences. A chemistry study found three official Chinese Semen Aesculi species separate clearly from each other, while European horse chestnut and Aesculus chinensis were similar. Sodium aescinate used in China comes from Aesculus wilsonii seeds; its safety findings do not automatically apply to European horse chestnut extract. ^{37 26}

Variable content in bark products. In commercial horse chestnut bark samples, esculin ranged from 25.89 to 38.94 mg/g dry weight; the authors say the variation shows a need for quality control. ²⁴

Standardisation. The EU monograph requires dry extracts standardised to 6.5 to 10% triterpene glycosides (calculated as protoaescigenin) for the well-established use and says the seed material must comply with the European Pharmacopoeia. The European Pharmacopoeia changed the assay in 2017, so older labels (16 to 28% as aescin) are not directly comparable. ⁴⁵

Look-alikes. NCCIH says the seeds resemble sweet chestnuts but taste bitter. Edible sweet chestnut (Castanea) is a different tree. ⁴⁸

Body	Action	Date
European Medicines Agency, Committee on Herbal Medicinal Products (HMPC) (European Union)	Herbal monograph on Aesculus hippocastanum L., semen (EMA/HMPC/628242/2018, final revision 1): well-established use of a standardised dry extract (oral) for chronic venous insufficiency; traditional use of cutaneous preparations for heavy legs and for bruises. Contraindication: hypersensitivity. Consult a doctor for renal or cardiac insufficiency, ulcers, thrombophlebitis, sudden swelling. Pregnancy, breastfeeding and under 18 not recommended. source	2020-01-15
NIH National Center for Complementary and Integrative Health (NCCIH) (United States)	Horse Chestnut: Usefulness and Safety. Raw seeds, bark, flowers and leaves unsafe by mouth; standardised seed extract likely safe short term; little known in pregnancy and breastfeeding. source

When to get medical help

Sudden swelling, pain or redness in one leg, especially with warmth, or chest pain and sudden breathlessness (possible blood clot).
Hives, swelling of lips or tongue, wheeze or fainting after taking it or using a gel (allergic reaction).
Yellow skin or eyes, dark urine or pale stools (liver).
Passing very little urine, new swelling around the eyes or ankles, or sudden tiredness with nausea (kidney).
Black stools, blood in vomit, unusual bruising or bleeding, especially if you take blood thinners.
Persistent vomiting or severe stomach pain after eating or snuffing conkers, bark or leaf.
A leg ulcer that is growing, painful or looks infected.
Rectal bleeding that does not stop or keeps returning.

Stop the supplement and contact a clinician or emergency service. In the US, Poison Control is 1-800-222-1222.

General information only, not medical advice. Ask a clinician or pharmacist before use, especially with medicines, in pregnancy or with a health condition. See the Natural Remedy Safety guide.

Frequently asked questions

Does horse chestnut work for varicose veins and swollen legs?

It probably helps symptoms of chronic venous insufficiency a little, with moderate certainty. Pooled trials found less leg swelling and pain than placebo. It does not remove varicose veins. Trials were mostly small and short, and the effect is modest.

^{27 32 11}

Is horse chestnut as good as compression stockings?

One large 12-week trial found a similar drop in swelling. That is one trial, and a later report found stockings worked better than the extract in advanced disease. Do not stop prescribed stockings without talking to your doctor.

^{11 23}

Is it safe to eat or drink raw conkers, bark or leaves?

No. NCCIH says raw seeds, bark, flowers and leaves are unsafe by mouth because they contain a toxic component. Only standardised seed extract has been studied. One teenager became unwell after snuffing powdered seeds.

^{48 42}

What is esculin and why does it matter?

Esculin is a coumarin-type compound found in the plant, with high levels in the bark. Raw plant parts are toxic and standardised extracts have the toxic component removed (NCCIH). The NCCIH page does not name that component, so we cannot say esculin is the cause. A skin reaction to an esculin extract has been reported.

^{48 24 7}

Can horse chestnut harm the kidneys or liver?

Rarely, as far as is known. The EU monograph says to consult a doctor if you have kidney insufficiency. LiverTox reports rare liver injury, and one 2021 case report exists. Injectable sodium aescinate from related seeds has been linked to kidney injury in lab studies. Frequency is not known.

^{45 22 9 44}

Does it interact with blood thinners?

It might. A 2000 review lists it with herbs said to strengthen warfarin, but gives no case data, and the EU monograph reports no interactions. Tell your doctor or pharmacist before combining it, and before surgery.

^{1 45}

Can I use horse chestnut with diabetes medicines?

No human data exist. Animal work found blood-sugar lowering with some seed saponins. Check your blood sugar and ask your doctor or pharmacist.

³¹

Is it safe in pregnancy or breastfeeding, or for children?

It is not recommended. The EU says safety has not been established in pregnancy or breastfeeding, and use under 18 is not recommended.

^{45 48}

What are the side effects?

Stomach upset, dizziness, headache and itching are the usual ones, and allergic reactions are possible. The Cochrane review said adverse events were usually mild and infrequent. Frequencies are not known.

^{45 48 27}

Does it help hemorrhoids?

Possibly. Two trials from one Thai research team found that adding escin to a flavonoid medicine stopped bleeding sooner and reduced recurrence. Escin was not tested alone, and rectal bleeding should be checked by a doctor.

^{30 35}

Does a horse chestnut gel help bruises?

Gels containing escin plus a salicylate eased pain on pressure after sports injuries better than placebo gel in short trials. It is not known if escin alone does the same. Do not apply to broken skin.

^{38 25 45}

What should I tell my doctor or pharmacist before using it?

Say if you take blood thinners, diabetes medicines or kidney-risk drugs, have liver or kidney disease, are pregnant or breastfeeding, or are about to have surgery. Ask them about amounts and which product is suitable.

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Is horse chestnut the same as sweet chestnut?

No. Horse chestnut seeds (conkers) look like sweet chestnuts but are bitter and unsafe raw. Sweet chestnut is a different tree.

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Editorial transparency

Written by: AlternativeMed editorial team. Research compiled with AI assistance, then checked against PubMed records.
Medical review: None. This page has not been reviewed by a physician or pharmacist.
First published: 2026-10-25
Last substantive update: 2026-10-25
How we research: We searched PubMed, the NIH NCCIH page and the EU herbal monograph (read in full), and recorded each study's design, people, product and result as reported. Only abstracts were read for the PubMed studies, and two records have no abstract. The EU assessment report, Commission E, WHO and the full LiverTox entry were not read. Ratings are ours unless a review gave its own.
How we rate evidence: See "How we rate evidence" in the Evidence tab.
Independence: No product is promoted on this page. No affiliate links are shown. If one is added later it will be labelled and kept apart from the evidence.

Sources 49

Each source was opened and checked. Where we read only the abstract, it says so. The small numbers in the text point here.

Argento A, Tiraferri E, Marzaloni M. [Oral anticoagulants and medicinal plants. An emerging interaction].. Ann Ital Med Int. 2000. PMID 10920504. (abstract)
Bisler H, Pfeifer R, Klüken N, et al.. [Effects of horse-chestnut seed extract on transcapillary filtration in chronic venous insufficiency].. Dtsch Med Wochenschr. 1986. PMID 3527643. DOI 10.1055/s-2008-1068628. (abstract)
Buso G, Santini P, Ghirardini F, et al.. Delphi Consensus on the Role of Venoactive Nutraceuticals in the Management of Chronic Venous Disease: A Position Statement of the Italian Society of Angiology and Vascular Medicine (SIAPAV).. Nutrients. 2025. PMID 41470775. DOI 10.3390/nu17243830. (abstract)
Bässler D, Okpanyi S, Schrödter A, et al.. Bioavailability of beta-aescin from horse chestnut seed extract: comparative clinical studies of two Galenic formulations.. Adv Ther. 2003. PMID 14964349. DOI 10.1007/BF02849858. (abstract)
Calabrese C, Preston P. Report of the results of a double-blind, randomized, single-dose trial of a topical 2% escin gel versus placebo in the acute treatment of experimentally-induced hematoma in volunteers.. Planta Med. 1993. PMID 8255928. DOI 10.1055/s-2006-959716. (abstract)
Chen C, Wang S, Chen J, et al.. Escin suppresses HMGB1-induced overexpression of aquaporin-1 and increased permeability in endothelial cells.. FEBS Open Bio. 2019. PMID 30972964. DOI 10.1002/2211-5463.12622. (abstract)
Comaish JS, Kersey PJ. Contact dermatitis to extract of horse chestnut (esculin).. Contact Dermatitis. 1980. PMID 7398276. DOI 10.1111/j.1600-0536.1980.tb03938.x. (summary-only)
Cosi V, Wildner S, Kapfhammer C, et al.. Allergic reactions to horse chestnut seeds are caused by mugwort pollen Art v 1-sensitization and represent a novel type of defensin-related allergy syndrome.. Allergy. 2025. PMID 39314061. DOI 10.1111/all.16335. (summary-only)
Costa Santos D, Lérias G, Madruga I. Drug-induced Liver Injury Due to a Horse Chestnut Dietary Supplement.. Eur J Case Rep Intern Med. 2021. PMID 33869100. DOI 10.12890/2021_002389. (abstract)
Diehm C, Vollbrecht D, Amendt K, et al.. Medical edema protection--clinical benefit in patients with chronic deep vein incompetence. A placebo controlled double blind study.. Vasa. 1992. PMID 1621440. (abstract)
Diehm C, Trampisch HJ, Lange S, et al.. Comparison of leg compression stocking and oral horse-chestnut seed extract therapy in patients with chronic venous insufficiency.. Lancet. 1996. PMID 8569363. DOI 10.1016/s0140-6736(96)90467-5. (abstract)
Fang Y, Zhao L, Yan F, et al.. Escin improves sperm quality in male patients with varicocele-associated infertility.. Phytomedicine. 2010. PMID 19682880. DOI 10.1016/j.phymed.2009.07.014. (abstract)
Gallelli L. Escin: a review of its anti-edematous, anti-inflammatory, and venotonic properties.. Drug Des Devel Ther. 2019. PMID 31631970. DOI 10.2147/DDDT.S207720. (abstract)
Gwozdzinski L, Pieniazek A, Gwozdzinski K. The Effect of Escin on the Plasma Membrane of Human Red Blood Cells.. Int J Mol Sci. 2025. PMID 41009489. DOI 10.3390/ijms26188923. (abstract)
Hu S, Belcaro G, Dugall M, et al.. Aescin-based topical formulation to prevent foot wounds and ulcerations in diabetic microangiopathy.. Eur Rev Med Pharmacol Sci. 2016. PMID 27831638. (abstract)
Huang Y, Zheng SL, Zhu HY, et al.. Effects of aescin on cytochrome P450 enzymes in rats.. J Ethnopharmacol. 2014. PMID 24252494. DOI 10.1016/j.jep.2013.11.016. (abstract)
Isola G, Matarese M, Ramaglia L, et al.. Efficacy of a drug composed of herbal extracts on postoperative discomfort after surgical removal of impacted mandibular third molar: a randomized, triple-blind, controlled clinical trial.. Clin Oral Investig. 2019. PMID 30311061. DOI 10.1007/s00784-018-2690-9. (abstract)
Jaspersen-Schib R, Theus L, Guirguis-Oeschger M, et al.. [Serious plant poisonings in Switzerland 1966-1994. Case analysis from the Swiss Toxicology Information Center].. Schweiz Med Wochenschr. 1996. PMID 8711457. (abstract)
Koch R. Comparative study of Venostasin and Pycnogenol in chronic venous insufficiency.. Phytother Res. 2002. PMID 11933130. DOI 10.1002/ptr.1010. (abstract)
Kuznetsov MR, Bogachev VY, Sapelkin SV, et al.. [The possibility of using local remedies to reduce the frequency of the 'string' symptom after radiofrequency obliteration of the trunk of the large saphenous vein].. Angiol Sosud Khir. 2025. PMID 41805617. DOI 10.33029/1027-6661-2025-31-4-110-117. (abstract)
Leach MJ, Pincombe J, Foster G. Clinical efficacy of horsechestnut seed extract in the treatment of venous ulceration.. J Wound Care. 2006. PMID 16620045. DOI 10.12968/jowc.2006.15.4.26898. (abstract)
LiverTox (NIDDK). Horse Chestnut.. . 2012. PMID 31643542. (abstract)
Ottillinger B, Greeske K. Rational therapy of chronic venous insufficiency--chances and limits of the therapeutic use of horse-chestnut seeds extract.. BMC Cardiovasc Disord. 2001. PMID 11747472. DOI 10.1186/1471-2261-1-5. (abstract)
Owczarek A, Kłys A, Olszewska MA. A validated (1)H qNMR method for direct and simultaneous quantification of esculin, fraxin and (-)-epicatechin in Hippocastani cortex.. Talanta. 2019. PMID 30348388. DOI 10.1016/j.talanta.2018.09.036. (abstract)
Pabst H, Segesser B, Bulitta M, et al.. Efficacy and tolerability of escin/diethylamine salicylate combination gels in patients with blunt injuries of the extremities.. Int J Sports Med. 2001. PMID 11531036. DOI 10.1055/s-2001-16251. (abstract)
Pan W, Zou X, Tang W, et al.. Sodium aescinate induces renal cell ferroptosis through the ATF4/CTH/SQOR axis.. Biochem Pharmacol. 2026. PMID 41759595. DOI 10.1016/j.bcp.2026.117847. (abstract)
Pittler MH, Ernst E. Horse chestnut seed extract for chronic venous insufficiency.. Cochrane Database Syst Rev. 2012. PMID 23152216. DOI 10.1002/14651858.CD003230.pub4. (abstract)
Rehn D, Unkauf M, Klein P, et al.. Comparative clinical efficacy and tolerability of oxerutins and horse chestnut extract in patients with chronic venous insufficiency.. Arzneimittelforschung. 1996. PMID 8737631. (abstract)
Rothkopf M, Vogel G, Lang W, et al.. Animal experiments on the question of the renal toleration of the horse chestnut saponin aescin.. Arzneimittelforschung. 1977. PMID 301389. (abstract)
Sanmee S, Vipudhamorn W, Sutharat P, et al.. The efficacy of Aescin combined with MPFF for early control of bleeding from acute hemorrhoids, A randomized controlled trial.. Asian J Surg. 2024. PMID 39153932. DOI 10.1016/j.asjsur.2024.07.336. (abstract)
Sharipov A, Tursunov K, Fazliev S, et al.. Hypoglycemic and Anti-Inflammatory Effects of Triterpene Glycoside Fractions from Aeculus hippocastanum Seeds.. Molecules. 2021. PMID 34206308. DOI 10.3390/molecules26133784. (abstract)
Siebert U, Brach M, Sroczynski G, et al.. 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. PMID 12518108. (abstract)
Sun W, Yin Q, Wan H, et al.. Characterization of the horse chestnut genome reveals the evolution of aescin and aesculin biosynthesis.. Nat Commun. 2023. PMID 37833361. DOI 10.1038/s41467-023-42253-y. (abstract)
Suter A, Bommer S, Rechner J. Treatment of patients with venous insufficiency with fresh plant horse chestnut seed extract: a review of 5 clinical studies.. Adv Ther. 2006. PMID 16644618. DOI 10.1007/BF02850359. (abstract)
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.. Ann Coloproctol. 2026. PMID 42392851. DOI 10.3393/ac.2025.01207.0172. (abstract)
Voigt E, Junger H. [Acute posttraumatic renal failure following therapy with antibiotics and beta-aescin (author's transl)].. Anaesthesist. 1978. PMID 637297. (abstract)
Wang WW, Liu ZW, Sun YZ, et al.. Comparison of Semen Aesculi species from different geographical origins and horse chestnut based on metabolomics and chemometrics analysis.. Phytochem Anal. 2023. PMID 36843182. DOI 10.1002/pca.3212. (abstract)
Wetzel D, Menke W, Dieter R, et al.. Escin/diethylammonium salicylate/heparin combination gels for the topical treatment of acute impact injuries: a randomised, double blind, placebo controlled, multicentre study.. Br J Sports Med. 2002. PMID 12055112. DOI 10.1136/bjsm.36.3.183. (abstract)
Wu X, Liu L, Zhang M, et al.. Simultaneous analysis of isomers of escin saponins in human plasma by liquid chromatography-tandem mass spectrometry: application to a pharmacokinetic study after oral administration.. J Chromatogr B Analyt Technol Biomed Life Sci. 2010. PMID 20185376. DOI 10.1016/j.jchromb.2010.02.002. (abstract)
Wu XJ, Zhang ML, Cui XY, et al.. Comparative pharmacokinetics and the bioavailability of escin Ib and isoescin Ib following the administration of escin, pure escin Ib and isoescin Ib in rats.. J Ethnopharmacol. 2014. PMID 24334163. DOI 10.1016/j.jep.2013.11.039. (abstract)
Xie Q, Zong X, Ge B, et al.. Pilot postoperative ileus study of escin in cancer patients after colorectal surgery.. World J Surg. 2009. PMID 19052813. DOI 10.1007/s00268-008-9816-1. (abstract)
Zając M, Wiśniewski M, Sein Anand J. [Intoxication by powdered seeds of horse chestnut (Aesculus hippocastanum) used nasally as snuff - a case report].. Przegl Lek. 2014. PMID 25632792. (abstract)
Zheng X, Tang X, Xu Y, et al.. Sodium aescinate induces hepatotoxicity through apoptosis and ferroptosis by inhibiting the Nrf2/CTH pathway.. J Ethnopharmacol. 2025. PMID 40064321. DOI 10.1016/j.jep.2025.119608. (abstract)
Zhu H, Yang Y, Duan Y, et al.. Nrf2/FSP1/CoQ10 axis-mediated ferroptosis is involved in sodium aescinate-induced nephrotoxicity.. Arch Biochem Biophys. 2024. PMID 39033970. DOI 10.1016/j.abb.2024.110100. (abstract)
. EU herbal monograph on Aesculus hippocastanum L., semen (horse-chestnut seed), Final - Revision 1 (EMA/HMPC/628242/2018, adopted 15 January 2020). . . (full-text)
. GBIF Backbone: Aesculus hippocastanum L. (usageKey 3189815). . . (full-text)
. NCBI Taxonomy: Aesculus hippocastanum (taxid 43364). . . (full-text)
. NIH NCCIH: Horse Chestnut, Usefulness and Safety. . . (full-text)
. PubChem compound records (name lookups): esculin, esculetin, escin, aescin, protoescigenin, fraxin, quercetin, kaempferol, epicatechin, procyanidin B2, warfarin. . . (full-text)

Where to buy

Check the label first. Whatever you buy, look for these:

The plant part and the extract type or ratio on the label
A standardized amount of the active compounds, where relevant
A third-party testing mark (USP, NSF or ConsumerLab)
Interactions: ask a pharmacist if you take medicines, are pregnant or have a medical condition

Talk to a pharmacist or doctor before you start any supplement, especially if you take medicines. See the Safety tab for interactions.

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Education, not medical advice. This page is for general information. It does not diagnose or treat any condition and is not a substitute for care from a qualified health professional. Natural does not automatically mean safe. Ask a clinician or pharmacist before changing your care, especially if you take medication, are pregnant or breastfeeding, or have a health condition.