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A digestive herb used by Native Americans, early settlers and present day practitioners alike

Black root

Veronicastrum virginicum Plantaginaceae

The dried roots of this graceful herb have beneficial effects on a sluggish digestion.

Sustainability Status

Sustainability status

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

Potential replacement(s): Greater celandine,

Key benefits
  • Chronic constipation
  • Spasm in the gut
  • Improving digestion
  • How does it feel?

    Culver’s root promotes a bitter taste. Culver’s root has a bitter and astringent taste that is cooling, descending and draining. It certainly feels cleansing with a potent effect on digestion.

  • What can I use it for?

    Used for sluggish digestion resulting in constipation and to improve liver function.

    Signs the digestion may be functioning under par might include a pale or coated tongue, intolerance to fatty foods, headaches, constipation or nausea, although it should be noted that these symptoms can also be indicators of other issues.

    Culver’s root is often combined with other hepatics (herbs with a beneficial action on liver function) such as dandelion root or barberry. It can also be combined with carminative herbs such as fennel seed, peppermint or ginger for assisted easing of bloating and spasm in the gut.

    Care needs to be taken with the dose as it has potential to cause diarrhoea and possibly vomiting if the doses are too high for the individual.

  • Into the heart of black root

    The active constituents within black root are bitter-tasting and cholagogue, thus they increase the flow of bile from the liver and assist with a sluggish bowel. The dried root can be described as a bitter tonic, helping with congestion in the bile ducts and gall bladder.

    Some historical accounts are conflicting and this may be down to the differences in action between the dried and fresh root. Use of the dried root if stored for a sufficiently long period before use and prescribed within an appropriate dosage range should not have drastic purgative actions, rather it should promote the secretion of bile without causing any negative effects on the digestive tract, having a gently toning effect on activity and easing constipation by its laxative effects.

    On the other hand the fresh root has deliberately been used in the past as a purging agent and as such was used to bring about a violent catharsis.

  • Traditional uses

    Veronicastrum, or Black root played a significant role in certain Native American rituals. The root of the plant has powerful purgative and emetic actions when used fresh and was used to induce vomiting as part of purification rituals.

    The Menomini used the plant for purification after being ‘defiled’ by being touched by a bereaved person.

    It was believed that the root cured typhus and ‘bilious fevers’, in part by inducing sweating.

    The mashed root was used to clean scrofula (tuberculous) sores by the Seneca and Ojibwa whilst the Cherokee chewed the plant to relieve the symptoms of colic and it was used to assist women in labour by the Meskwaki.

    A couple of the plant’s common names come from a Dr Culver, an eighteenth-century physician who promoted the use of the plant amongst settlers as a remedy for chronic constipation and ‘liverish’ conditions, hence Culver’s root and Culver’s physic.

    It was once included in the United States Pharmacopoeia, however it isn’t in such common use these days, possibly due to its reputation as a powerful cathartic when used fresh.

  • 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

    Black root is indicated for chronic constipation. It is a cholagogue and thus promotes the flow of bile from the gall bladder into the duodenum, increasing digestive activity such as motility and appetite and causing a dose-dependent laxative effect.

    In standard doses the dried root can strengthen the functional activity of the organs associated with digestion such as the liver and pancreas and can be of benefit in gallbladder and bile disorders such as cholecystitis (inflammation of the gall bladder).

    Skin and musculoskeletal: Herbalists will often use medicinal plants which have an action on the liver and digestion to promote elimination along with other herbal protocols in the treatment of chronic skin and joint conditions. Black root can be included here as one such herb.

  • Research

    Evidence-based research on the medicinal properties of Black root is extremely scant. One preliminary study has been carried out on the anti-acne and antioxidant effects of this herb along with Yarrow (Achillea millfolium).

    Extracts of whole herb powder of Yarrow and root powder extracts of Black root were used. Minimum Inhibitory Concentration (MIC) was established for anti-microbial activity against two acne causing bacteria: Propionibacterium acnes and Staphylococcus epidemidis. An ethanolic extract for both plants demonstrated the highest free radical scavenging activity.

    Further research, especially into the effects of Black root on the liver and digestion are certainly required.

  • Did you know?

    Early Anglo-settlers in America adopted the use of Black root for purgative use as prior to this one of the principle purgatives was mercury!

    It is said that the early settlers would put the root into ‘war bundles’, used to purify people, animals, medicines and weapons.

Additional information

  • Botanical description

    This single species of hardy perennial belonging to the genus
    Veronicastrum occurs in eastern North America. A graceful upright
    perennial with whorls of finely-toothed slender leaves and horizontal black rhizomes.

    The small, delicate tubular flowers are borne in clusters of dense spikes during summer and early autumn. Their colour ranges from white, blue or pink to purple. The plant can grow to a height of 2 metres with a spread of around a metre.

    Introduced into European gardens in 1714 it proved very popular planted along the back of a border due to the tall and elegant spires of flowers. It prefers a sunny spot but will tolerate a bit of shade, and tolerates most soils providing they hold a bit of moisture. Both long and short-tongued bees greatly enjoy the nectar provided by the flowers.
    The roots and rhizomes are the parts used medicinally and are harvested in the autumn. The dried roots should be stored for a year before use to lessen their laxative potency.

  • Common names

    • Black root
    • Culver’s root
    • Culver’s physic
    • Tall speedwell
    • Bowman’s root
    • Beaumont’s root
    • Leptandra-wurzel
    • Whorlywort
  • Safety

    Black root stimulates the flow of bile (which aids in digestion, absorption and excretion) but if the fresh root is taken, then the effect can be ‘violently purgative’, inducing vomiting and diarrhoea, sometimes with bloody stools.

    These drastic actions are far less of a risk when the root is dried and are further reduced by storing for one year before processing into medicines. It should be taken in small doses, working up over a period of time only if required.

  • Contraindications

    Contraindicated in children, during pregnancy and lactation.

  • Dosage

    5–10g dried rhizome as a decoction up to three times daily. Start with low doses.

  • Constituents

    • A bitter compound: Leptandrin
    • Tannins
    • Volatile oils
    • Cinnamic acid derivatives
    • A glycoside resembling Senegin
    • Resin
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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