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Horse chestnut is used to treat localised conditions in the cardiovascular system

Horse chestnut

Aesculus hippocastanum Sapindaceae

In Germany, horse chestnut topical and oral extracts are available on prescription to treat varicosities and chronic venous insufficiency.

Sustainability Status

Sustainability status

At risk from overharvesting and habitat loss. Read more about our sustainability guide.

Key benefits
  • Anti-oedema
  • Haemorrhoids
  • Chronic venous insufficiency
  • Various veins
  • Leg vein health
  • How does it feel?

    Horse chestnut tincture is powerfully bitter to taste.

  • What can I use it for?

    Horse chestrnut tree (Aesculus hippocastanum)
    Horse chestrnut tree (Aesculus hippocastanum)

    The raw seeds, bark, flowers, and leaves of horse chestnut contain toxic compounds and are therefore unsafe for use internally unless using an extract that has been standardised to remove the toxic constituents (3). 

    For this reason, it is best to source horse chestnut extracts from reputable suppliers. There are many horse chestnut seed products that are safe for internal and oral use as they have either been standardised or the toxic compounds have been removed. These can be found in most independent health food stores and appear to be safe for short-term use. It is important to note that no parts of the horse chestnut tree should be eaten raw as it contains significant amounts of a poison called aesculin and can be fatal if significant quantities are eaten raw (3).

    Many capsules and standardised extracts can be taken internally. These are often marketed for the treatment of varicose veins or other localised conditions where the veins become enlarged, dilated, and congested (2).

    Horse chestnut extracted in a gel, cream or ointment is used to treat haemorrhoids and varicose veins. Horse chestnut works by protecting the small veins and capillaries due to its antioxidant tannin content (2). The topical use of horse chestnut is safe providing used on unbroken skin.

    Both the extract of horse chestnut and the topical preparations of horse chestnut are used to relieve symptoms of discomfort and heaviness of legs related to minor venous circulatory disturbances and for relief of signs of bruises, such as local oedema and haematoma (1).

    Horse chestnut topical preparations offer relief from night cramps and congestion in the lower limbs, classified by pain, itching and swelling as well fatigued, heavy legs (5). It may also be used for restless leg syndrome (7).

  • Into the heart of horse chestnut

    The energetics of horse chestnut are cool and dry as well as being powerfully bitter and astringent. The dynamic effect of horse chestnut makes it an important protector of vascular structures and microcirculation. 

    In TCM (Traditional Chinese Medicine) it is specifically indicated for the liver and bladder meridians. It is also referenced as a medicine that tonifies and moves the blood, stopping bleeding (6) due to its ability to heal and support the vascular walls (5).

    Horse chestnut combines well with lime flowers and yarrow to strengthen and support the blood vessels, and with chilli or hawthorn to improve circulation.

  • Traditional uses

    The first written account of medicinal uses in the West in 1720 referenced horse chestnut as being used to treat rheumatism and rectal complaints (2). In the 19th century it was used for bladder, gastrointestinal disorders, fever and haemorrhoids and leg cramps (2).

    In 1960 researchers identified that the anti-oedematous and vaso-protective properties of horse chestnut seed were exclusively attributable to a compound called aescin. Horse chestnut seed extract has since been widely prescribed in Europe for the treatment of venous insufficiency and vascular fragility (4).

  • Traditional actions

  • Traditional energetic actions

    Herbal energetics are the descriptions Herbalists have given to plants, mushrooms, lichens, foods, and some minerals based on the direct experience of how they taste, feel, and work in the body. All traditional health systems use these principles to explain how the environment we live in and absorb, impacts our health. Find out more about traditional energetic actions in our article “An introduction to herbal energetics“.

  • What practitioners say

    Horse chestnut flowers (Aesculus hippocastanum)
    Horse chestnut flowers (Aesculus hippocastanum)

    Cardiovascular system

    Horse chestnut is primarily used for conditions in the cardiovascular system such as chronic venous insufficiency. This condition is characterised by swollen legs, varicose veins, heaviness, pain, tiredness, itching, tension and cramps in the calves (1).

    Other conditions where horse chestnut is commonly indicated include haemorrhoids, various veins and post-operative oedema (2).

    Horse chestnut has a number of actions enabling therapeutic effects on vascular structures. It increases venous tone and improves capillary resistance and permeability. It tones the veins, decreases oedema through direct localised healing effects on the vasculature, and encourages lymphatic activity, reducing both inflammation and congestion (5).

    One of the key compounds involved in horse chestnut’s ability to decrease vascular permeability is aescin. Aescin has been shown to elicit anti-oedematous, anti-inflammatory, and venotonic properties. Horse chestnut increases sensitisation to calcium ions, enhancing venous contractile activity and decreasing capillary permeability. These combined actions improve venous tone thus producing a sealing effect upon the weakened or affected vascular tissues thereby reducing oedema and swelling (2, 5).

    Horse chestnut may also be used by herbalists as part of a prophylactic approach for deep vein thrombosis as well as for presentations with a higher risk of developing chronic venous insufficiency (5).

  • Research

    Horse chestnut (Aesculus hippocastanum)
    Horse chestnut (Aesculus hippocastanum)

    Research including clinical trials, in vivo and in vitro studies have investigated the uses of horse chestnut for many decades. Some of this has been carried out using standardised whole plant extracts as well as isolated compounds of horse chestnut, mainly focusing on its use in diseases of the cardiovascular system. 

    Animal studies are not condoned by herbal reality, however, to include research from which some understanding of therapeutic actions can be confirmed, some animal studies have been included.

    Chronic venous insufficiency

    In a 2012 systematic review encompassing 17 studies, findings demonstrate the effects of horse chestnut seed extract alleviate symptoms associated with chronic venous insufficiency (CVI). Notably, results from one of these studies suggest comparable effectiveness of horse chestnut to wearing compression stockings (3).


    In a double-blind, placebo-controlled trial participants with acute symptomatic haemorrhoids were administered horse chestnut seed extract (HCSE) in the form of 40 mg aescin tablets three times daily for two months. The results demonstrated a significant improvement in symptoms with  reduced bleeding within less than a week of treatment confirmed through endoscopic evaluation. 

    Out of the 38 patients receiving aescin, 31 (82%) reported notable reduction of pain, itching, burning, and swelling, in contrast to only 11 of the 34 (32%) in the placebo group. Endoscopic assessment revealed a significant reduction in bleeding for 26 patients in the aescin group compared to 13 in the placebo group, along with decreased swelling reported by 29 patients in the aescin group compared to 12 in the placebo group (2).

    Deep vein thrombosis

    A large-scale, randomised controlled trial was carried out on horse chestnut on 4176 patients with thrombosis lung infection and lung embolism to investigate the prophylactic potential of horse chestnut in post-surgical risk of thrombotic conditions.

    Horse chestnut was administered intravenously at 10ml a day in the treatment group, the control received either strophanthin or digitalis, vitamin B complex and vitamin C for 4 days prior to surgery and 7 days post surgery. The study results showed that horse chestnut significantly reduced the incidence of deep vein thrombosis after surgery (5).

    Male infertility

    Limited research has explored the potential benefits of horse chestnut seed extract in addressing male infertility linked to varicocele (swelling of veins inside the scrotum) as well as irritable bowel syndrome. However, the available information is insufficient to make definitive conclusions about its efficacy for either condition. Further research and larger-scale clinical trials are required to elucidate the potential of horse chestnut as a treatment option for these conditions (3).

  • Did you know?

    The common name, ‘horse chestnut’ is thought to originate from the resemblance of brown conkers to chestnuts and the horseshoe-shaped mark, complete with spots resembling horseshoe nails, left on the twig when the leaves shed in autumn.

    One of the key active constituents in horse chestnut ‘aescin’ (or escin) is a registered drug in Germany. It is prescribed both topically and orally for the treatment of peripheral vascular diseases (5).

Additional information

  • Botanical description

    Horse chestnut is a rapidly growing large deciduous tree. It is capable of reaching a height of 36 meters. Its flowers appear as clusters in white or pink with a small red spot. Its leaves are large, tear-drop shaped, and composed of either five or seven leaflets. The tree produces a round fruit with a thick, green, spiny husk enclosing a glossy brown seed known as a chestnut or conker.

  • Common names

    • Horse-chestnut
    • European horse chestnut
    • Buckeye
    • Conker tree
  • Safety

    Horse chestnut is not recommended for use in pregnancy and lactation. It is important to stay within the recommended dosage for this herb due to the potentially toxic nature of some of its constituents (5).

    As a saponin-containing herb oral use of horse chestnut may cause gastric mucous membrane irritation and reflux. Enteric-coated preparations may be used for those who have sensitive digestive systems or for those using horse chestnut more long-term.

  • Interactions

    Horse chestnut may interact with anticoagulant medications. If you are taking medications that affect your blood coagulation consult a qualified professional before using horse chestnut extracts.

  • Contraindications

    Horse chestnut should not be applied to broken or ulcerated skin (5). If using for haemorrhoids stop use of topical horse chestnut immediately should bleeding occur.

  • Preparation

    • Tablets
    • Capsules
    • Tincture
  • Dosage

    There are many standardised extracts of horse chestnut available over the counter. Horse chestnut tablets are often used over liquid preparations due to the reduced risk of gastric irritation. Follow the recommended dosage as per the product or professional instruction.

    Horse chestnut tablets: Take 2-3 tablets per day (200mg of 5:1 concentration standardised to include 40mg aescin) (5).

    Tincture (1:5 in 35%): Take between 1-5ml in a little water up to 3 times a day (5).

  • Plant parts used


  • Constituents

    The primary active constituent found in horse chestnut seed extract is aescin which is a mixture of α and β triterpene saponins (2).

    Other constituents include bioflavonoids (quercetin and kaempferol), proanthocyanidin A2 which has antioxidant properties, and the coumarins fraxin and aesculin (2).

    The anti-edematous and vasoprotective properties are thought to be exclusively due to aescin (2).

    Of the two forms of aescin, β-aescin is the active component in the saponin mixture and the form found in most HCSE pharmaceuticals used for venous insufficiency (2).

Horse chestnut illustration (Aesculus hippocastanum)
  • Habitat

    Horse chestnut is native to parts of southeastern Europe. It is thought to originate from the Balkan Peninsula.

  • Sustainability

    According to the IUCN Red List of Threatened Plants Status horse chestnut is classified as vulnerable as its population is decreasing. It is affected by deforestation, exploitation, mining, tourism development and other threats, even in some protected areas. Populations are considered to be severely fragmented. The IUCN (7) states ‘the species has been assessed as threatened across most of its native range. It is Endangered in Bulgaria and critically endangered in Albania. In Greece, the declining population is estimated at less than 1,500 adult trees, whilst in Albania, the population does not exceed 500 individuals (7)’.

    Habitat loss and over-harvesting from the wild are two of the biggest threats faced by medicinal plant species. There are an increasing number of well-known herbal medicines at risk of extinction. We must therefore ensure that we source our medicines with sustainability in mind. 

    The herb supplement industry is growing at a rapid rate and until recent years a vast majority of medicinal plant produce in global trade was of unknown origin. There are some very real and urgent issues surrounding sustainability in the herb industry. These include environmental factors that affect the medicinal viability of herbs, the safety of the habitats that they are taken from, as well as the welfare of workers in the trade.

    The botanical supply chain efforts for improved visibility (transparency and traceability) into verifiably sustainable production sites around the world is now certificated through the emergence of credible international voluntary sustainability standards (VSS). 

    Read our article on Herbal quality & safety: What to know before you buy  and Sustainable sourcing of herbs to learn more about what to look for and questions to ask suppliers about sustainability.

  • Quality control

    Herbal Medicines are often extremely safe to take, however it is important to buy herbal medicines from a reputed supplier. Sometimes herbs bought from unreputable sources are contaminated, adulterated or substituted with incorrect plant matter.

    Some important markers for quality to look for would be to look for certified organic labelling, ensuring that the correct scientific/botanical name is used and that suppliers can provide information about the source of ingredients used in the product.

    A supplier should be able to tell you where the herbs have come from. There is more space for contamination and adulteration when the supply chain is unknown.

  • How to grow

    Horse chestnut conkers (Aesculus hippocastanum)
    Horse chestnut conkers (Aesculus hippocastanum)

    Horse chestnut is easy to grow. The seeds can easily be found in parks, gardens and arboretums. The seeds are planted in late autumn, before the first frost (Around October to November).

    • Carefully open the green spiky seed husks to remove the brown seed (conkers). Submerge the seeds (or ‘conkers’) in a bucket of water, any that float to the top are dead and will not grow.
    • Prepare small pots with a mixture of soil and compost (70%/30%) making a 2cm hole in the soil in which to place the seed. 
    • The seeds will require 4 hours of sunshine in order to germinate. Water the soil when it starts to dry out. The seeds should sprout in the spring after planting.
    • Note: To give your tree seeds that best chance- make sure to keep the pots out of reach from birds and squirrels.
    • Once the seedlings have grown to saplings, they will need to be transferred into bigger pots or the ground when they reach roughly 0.3m – which could take up to a year.


  • References

    1. European Union herbal monograph on Aesculus hippocastanum L., semen Draft -Revision 1. (2008). https://www.ema.europa.eu/en/documents/herbal-monograph/draft-european-union-herbal-monograph-aesculus-hippocastanum-l-semen-revision-1_en.pdf
    2. Aesculus hippocastanum (Horse chestnut). (n.d.). https://altmedrev.com/wp-content/uploads/2019/02/v14-3-278.pdf
    3. Pittler, M. H., & Ernst, E. (2012). Horse chestnut seed extract for chronic venous insufficiency. Cochrane Database of Systematic Reviews. https://doi.org/10.1002/14651858.cd003230.pub4 Aesculus hippocastanum – an overview ScienceDirect Topics. (n.d.). Www.sciencedirect.com. Retrieved November 29, 2023, from https://www.sciencedirect.com/topics/pharmacology-toxicology-and-pharmaceutical-science/aesculus-hippocastanum
    4. Bone, K., & Mills, S. (2013). Principles and Practice of Phytotherapy: Modern Herbal Medicine (2nd ed.). Edinburgh Churchill Livingstone, Elsevier.
    5. Horse Chestnut (Qi Ye Shu) | East West Healing Academy. (n.d.). White Rabbit Institute of Healing. Retrieved November 30, 2023, from https://www.whiterabbitinstituteofhealing.com/herbs/horse-chestnut/
    6. Aesculus hippocastanum. (2011, October 19). The Naturopathic Herbalist. https://thenaturopathicherbalist.com/herbs/a-2/aesculus-hippocastanum-horse-chestnut/
    7. Allen (IUCN), D., & Group), S. K. (Cave I. S. (2017, July 20). IUCN Red List of Threatened Species: Horse Chestnut. IUCN Red List of Threatened Species. https://www.iucnredlist.org/species/202914/122961065
An ‘aromatic’ remedy, high in volatile essential oils, was most often associated with calming and sometimes ‘warming’ the digestion. Most kitchen spices and herbs have this quality: they were used both as flavouring and to ease the digestion of sometimes challenging pre-industrial foods. Many aromatics are classed as ‘carminatives’ and are used to reduce colic, bloating and agitated digestion. They also often feature in respiratory remedies for colds, chest and other airway infections. They are also classic calming inhalants and massage oils, and are the basis of aromatherapy for their mental benefits.
Astringent taste
The puckering taste you get with many plants (the most familiar is black tea after being stewed too long, or some red wines) is produced by complex polyphenols such as tannins. Tannins are used in concentrated form (eg from oak bark) to make leather from animal skins. The process of ‘tanning’ involves the coagulation of relatively fluid proteins in living tissues into tight clotted fibres (similar to the process of boiling an egg). Tannins in effect turn exposed surfaces on the body into leather. In the case of the lining of mouth and upper digestive tract this is only temporary as new mucosa are replenished, but in the meantime can calm inflamed or irritated surfaces. In the case of open wounds tannins can be a life-saver – when strong (as in the bark of broadleaved trees) they can seal a damaged surface. One group of tannins, the reddish-brown ‘condensed tannins’ are procyanidins, which can reduce inflammation and oxidative damage.
Bitters are a very complex group of phytochemicals that stimulate the bitter receptors in the mouth. They were some of the most valuable remedies in ancient medicine. They were experienced as stimulating appetite and switching on a wide range of key digestive functions, including increasing bile clearance from the liver (as bile is a key factor in bowel health this can be translated into improving bowel functions and the microbiome). Many of these reputations are being supported by new research on the role of bitter receptors in the mouth and elsewhere round the body. Bitters were also seen as ‘cooling’ reducing the intensity of some fevers and inflammatory diseases.
Blue-purple colouring
Any fruits with a blue-purple colouring contain high levels of the polyphenols known as anthocyanins. These work 1) on the walls of small blood vessels, helping to maintain capillary structure to reduce a key stage in inflammation, and improving the microcirculation to the tissues; 2) to improve retinal function and vision; 3) to support connective tissue repair around the body.
Traditional ‘cold’ or cooling’ remedies often contain bitter phytonutrients such a iridoids (gentian), sesiquterpenes (chamomile), anthraquinones (rhubarb root), mucilages (marshmallow), some alkaloids and flavonoids. They tend to influence the digestive system, liver and kidneys. Cooling herbs do just that; they diffuse, drain and clear heat from areas of inflammation, redness and irritation. Sweet, bitter and astringent herbs tend to be cooling.
Traditional ‘hot’ or ‘heating’ remedies, often containing spice ingredients like capsaicin, the gingerols (ginger), piperine (black or long pepper), curcumin (turmeric) or the sulfurous isothiocyanates from mustard, horseradich or wasabi, generate warmth when taken. In modern times this might translate as thermogenic and circulatory stimulant effects. There is evidence of improved tissue blood flow with such remedies: this would lead to a reduction in build-up of metabolites and tissue damage. Heating remedies were used to counter the impact of cold, reducing any symptoms made worse in the cold. .
Mucilages are complex carbohydrate based plant constituents with a slimy or ‘unctuous’ feel especially when chewed or macerated in water. Their effect is due simply to their physical coating exposed surfaces. From prehistory they were most often used as wound remedies for their soothing and healing effects on damaged tissues. Nowadays they are used more for these effects on the digestive lining, from the throat to the stomach, where they can relieve irritation and inflammation such as pharyngitis and gastritis. Some of the prominent mucilaginous remedies like slippery elm, aloe vera and the seaweeds can be used as physical buffers to reduce the harm and pain caused by reflux of excess stomach acid. Mucilages are also widely used to reduce dry coughing. Here the effect seems to be by reflex through embryonic nerve connections: reduced signals from the upper digestive wall appear to translate as reduced activity of airway muscles and increased activity of airway mucus cells. Some seed mucilages, such as in psyllium seed, flaxseed (linseed) or guar bean survive digestion to provide bulking laxative effects in the bowel. These can also reduce rate of absorption of sugar and cholesterol. .
New-mown hay aroma
The familiar country odour of haymaking, of drying grass and other plants, is largely produced by coumarins (originally isolated from tonka beans – in French coumarou) and widely used in perfumery. They are chemically categorised as benzopyrone lactones and are important phytochemicals, with strong antioxidant activity in the laboratory and likely effects in modulating inflammation. They were most often associated with the calming effect linked to their use in stuffing mattresses and pillows and plants, high In coumarins were commonly used for these properties.
Resins are most familiar as tacky discharges from pine trees (and as the substance in amber, and rosin for violin bows). They were most valued however as the basis of ancient commodities like frankincense and myrrh (two of the three gifts of the Three Wise Men to the baby Jesus) and getting access to their source was one benefit to Solomon for marrying the Queen of Sheba (now Ethiopia). Resins were the original antiseptic remedies, ground and applied as powders or pastes to wounds or inflamed tissues, and were also used for mummification. With alcohol distillation it was found that they could be dissolved in 90% alcohol and in this form they remain a most powerful mouthwash and gargle, for infected sore throats and gum disease. They never attracted much early research interest because they permanently coat expensive glassware! For use in the mouth, gums and throat hey are best combined with concentrated licorice extracts to keep the resins in suspension and add extra soothing properties. It appears that they work both as local antiseptics and by stimulating white blood cell activity under the mucosal surface. They feel extremely effective!
The salty flavour is immediately distinctive. A grain dropped onto the tongue is instantly moistening and a sprinkle on food enkindles digestion. This easily recognisable flavour has its receptors right at the front of the tongue. The salty flavor creates moisture and heat, a sinking and heavy effect which is very grounding for the nervous system and encourages stability. People who are solid and reliable become known as ‘the salt of the earth'.
The sharp taste of some fruits, and almost all unripe fruits, as well as vinegar and fermented foods, is produced by weak acids (the taste is generated by H+ ions from acids stimulating the sour taste buds). Sour taste buds are hard-wired to generate immediate reflex responses elsewhere in the body. Anyone who likes the refreshing taste of lemon or other citrus in the morning will know that one reflex effect is increased saliva production. Other effects are subjective rather than confirmed by research but there is a consistent view that they include increased digestive activity and contraction of the gallbladder.
In the days when most people never tasted sugar, ‘sweetness’ was associated with the taste of basic foods: that of cooked vegetables, cereals and meat. In other words sweet was the quality of nourishment, and ‘tonic’ remedies. Describing a remedy as sweet generally led to that remedy being used in convalescence or recovery from illness. Interestingly, the plant constituents most often found in classic tonics like licorice, ginseng are plant steroids including saponins, which also have a sweet taste.

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