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Centaury is extremely bitter, a great stimulant for the digestive system

Centaury

Centaurium erythraea

Gentianaceae

The bitterness of centaury makes it a powerful herb for the digestive system. It stimulates the appetite and supports the healthy functioning of the liver and gallbladder.

Sustainability status

Not currently on risk lists but complete data may be missing on the status of the species. Read more about our sustainability guide.

Sustainability Status
Key benefits
  • Digestive system support
  • Appetite stimulant
  • Liver support
  • Gallbladder support
  • Bitter
  • How does it feel?

    An infusion of centaury is golden yellow, and smells slightly sour and salty, which is deceptively inviting to take a sip.  

    The taste is bitter with a capital B! The sensation in the mouth is an acrid bitterness which hits as soon as the infusion touches the tongue, and further intensifies after swallowing. This is not a tea for delightful enjoy; this is a potent medicine to stimulate digestion. The tincture has the same intense, bitter, acrid taste. For a few minutes after taking centaury, it may ignite feelings of light-headedness as the bitter receptors on the tongue send a wave of signals through the central nervous system. This sensation then rapidly moves downwards through the body. The mouth is left feeling watery as the salivary glands are stimulated. With the bitter taste still lingering in the mouth, the attention will be drawn to the stomach with sensations of digestive simulation. It is possible to both feel and hear the digestive juices being released and moving around the stomach and into the intestines. The bitterness of centaury works rapidly, and appetite stimulation is felt shortly after consuming it. As outlined by Waddell in his collection of the teachings of Christopher Hedley, “the downward activity of bitters, experienced with tasting it, is key to their therapeutic application” (1).

  • What can I use it for?

    Centaury (Centaurium erythraea)
    Centaury (Centaurium erythraea)

    Centaury is an extremely bitter herb in the Gentianaceae family, related to the more commonly used yellow gentian (Gentiana lutea). Centaury is native to the UK and grows wild across much of Europe. It is the aerial (above ground) parts of centaury which are used as medicine. This is in comparison to gentian where the root is typically used, which damages or kills the plant when harvesting for medicine. Although the whole gentian family is on the United Plant savers “at risk” list due to over-harvesting from the wild, centaury is not one of the priority species of concern (2). Given that the aerial parts of centaury are used as medicine, it is a more responsible alternative to gentian, where the roots are harvested. Gentian is also listed by the Convention on the Conservation of European Wildlife and Natural Habitats, which prohibits wild harvesting, regulates sales and encourages propagation (3). 

    Centaury is useful whenever a digestive or gastric stimulant is needed to support dyspepsia (indigestion), sluggish digestion, nausea or bloating after a meal. Centaury contains bitter glycosides which stimulate bile flow (4). This helps to improve digestion and appetite and has a toning effect on the liver and gallbladder, effectively strengthening digestive function (5,6). It is one of the herbs used in Vermouth and other bitter liqueurs traditionally drunk as an aperitif before meals to stimulate the appetite (7). It can be used for weak digestion, poor appetite, heartburn, nausea, intestinal parasites, jaundice, gallstones, and liver congestion (7). 

    Centaury has a febrifuge action and can be used to reduce a fever (7). Centaury has an affinity for the nervous system, known to lift the spirits and calm the nerves (7). These combined effects on the digestive, immune and nervous systems provide a strengthening effect when recovering from illness, long-term stress, chronic fatigue and post-viral syndrome (7,8). 

    Centaury can be used both internally and externally for skin eruptions, eczema and boils (8). Skin conditions are often related to poor digestion and elimination, and centaury supports these eliminative processes. Topically, centaury is anti-inflammatory and antiseptic, and an infusion can be applied to cuts, grazes, boils and ulcers (7). The fresh green herb can also be applied externally to wounds and sores (5). 

  • Into the heart of centaury

    Centaury (Centaurium erythraea)
    Centaury (Centaurium erythraea)

    There are a range of constituents which account for the bitter taste, collectively referred to as the bitter principles. The bitter principles in centaury are monoterpene iridoids, secoiridoids and alkaloids (9,10). Bitters have broad effects on the digestive system, indirectly affecting the functioning of many body systems and holistically supporting the whole body (4). There is no better time to consider the importance of taste than when considering bitter herbs. The bitter taste works through the central nervous system to create a cascade of effects throughout the digestive tract. The bitter taste is detected by the taste buds, which are specialised sensory cells on the tongue and in the mouth, which detect the bitter constituents and send a neural message through the central nervous system (4). This leads to a range of effects in the digestive system including: production and secretion of pepsin and hydrochloric acid in the stomach; stimulation and release of digestive juices from the pancreas and small intestine; stimulation of the flow of bile from the liver and gall bladder; and, toning and protecting the gut wall in the intestines (4,11).

    Bitter herbs support digestion, clear congestion from the liver, normalise disordered peristalsis (which causes IBS symptoms), and protect the liver and kidneys from toxic damage (1). Physically, this clears heat and inflammation from the liver, stomach, spleen, and blood, which can present as symptoms of fever or rashes (1). Therefore, centaury is physically and energetically cooling (11). This energetic cooling can prevent heat from rising, which can manifest as anger, an erratic heartbeat, and manic behaviour (1). Centaury is related to the expression of rage, acting on the solar plexus and throat chakras (8). It helps a person to stand up for themselves and not let other people take advantage of them(8). 

    A homeopathic remedy is used in the treatment of liver and gall bladder ailments (5). As a flower essence, centaury is for people that are very sensitive to others and the environment and can easily be hurt or become ill as a result of these negative influences (7). It is for those who are timid, fearful and submissive, who become easily dominated by more forceful characters (8). Centaury is useful for people who easily offer themselves up for sacrifice, providing the courage to stand up for their beliefs (8). Centaury helps with the development of will, and the recognition that individuality is valuable and necessary (7). Drink an infusion of centaury in the morning in order to face the day with courage (8).

  • Traditional uses

    Centaury (Centaurium erythraea)
    Centaury (Centaurium erythraea)

    Centaury is so bitter the ancient Romans referred to it as fel terrae, meaning “bile of the earth”, recognised for its power to stimulate the digestive system (12). 

    In 1640, Parkinson included centaury in his Theatrum Botanicum as a cleansing bitter herb, used to increase bile flow and support the liver, gallbladder, and spleen (6). It was also valued as a febrifuge, clearing heat from the body during a fever (6). He refers to the fact that the herb has been used since Dioscorides, Pliny and Galen (1–200AD) as an infusion to purge choleric and gross humours (6). Purging choleric and gross humours refers to the ancient medical practice of removing excess yellow bile and other imbalanced bodily fluids to restore optimal health. The Saxons used it for snake bites and intermittent fevers, leading to one of the common names, feverwort (7).

    Culpeper’s 1653 Complete Herbal stated that drinking the herb opens obstructions of the liver, gallbladder and spleen, eases pain in the spleen and helps with jaundice (13). It was also taken to “kill worms in the belly”, and ease joint pain, gout and muscle cramps (13). Externally, it was applied as the bruised, fresh herb to cleanse and close fresh wounds, old ulcers and sores (13). A decoction of the leaves, stalks and flowers was used to “bring down women’s courses”, referring to inducing menstruation or regulating the menstrual cycle, as well as to “avoid the dead birth, and ease the pains of the mother” (13). The powder added to a dram of wine was considered a “wonderfully good help against the biting and poison of an adder” (13). Culpeper summarised the herb by referring to the bitter and unpalatable taste, stating, “Tis very wholesome, but not very toothsome” (13). 

    In 1918, British herbalist Richard Lawrence Hool wrote of centaury as a stomachic, bitter, tonic, valuable for stimulating an appetite and toning the digestive system (14). It was used for obstruction of the liver, general malaise, and to act upon the heart as a general strengthener, recommended as an infusion (14). It was considered an excellent tonic for delicate and elderly people, combined in the following way with one pint (~500 ml) of boiling water, and taken in wineglassful doses four times a day: centaury, ½ oz (~15 g) and raspberry leaves, ½ oz (~15 g) (14).

    Grieve, in 1931, wrote of centaury as an aromatic bitter, excellent as a simple tonic acting on the liver and kidneys and purifying the blood (15). It was used extensively for dyspepsia, slow digestion, heartburn after food, poor appetite, and muscular rheumatism (15). It was combined with barberry bark (Berberis vulgaris) for jaundice, and as a vermifuge to “destroy body vermin” (15).

  • Traditional actions

    Herbal actions describe therapeutic changes that occur in the body in response to taking a herb. These actions are used to express how a herb physiologically influences cells, tissues, organs or systems. Clinical observations are traditionally what have defined these actions: an increase in urine output, diuretic; improved wound healing, vulnerary; or a reduction in fever, antipyretic. These descriptors too have become a means to group herbs by their effects on the body — herbs with a nervine action have become the nervines, herbs with a bitter action are the bitters. Recognising herbs as members of these groups provides a preliminary familiarity with their mechanisms from which to then develop an understanding of their affinities and nuance and discern their clinical significance.

  • 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

    Centaury (Centaurium erythraea)
    Centaury (Centaurium erythraea)

    Digestive system

    Centaury is suited to a range of issues related to the digestive tract, including weakened digestion, and lack of appetite. The bitter glycosides increase the production of pepsin and hydrochloric acid in the stomach, promote the flow of bile from the liver and gall bladder, stimulate the release of digestive juices from the pancreas, and, tone and repair the gut wall in the intestines (4,11). The British Herbal Pharmacopoeiai recommends centaury as a carminative for dyspepsia and for loss of appetite (anorexia) in children and the elderly (10). Other herbs with a similar action on the digestive system are: dandelion root, artichoke leaf, andrographis and gentian

    Stomach

    Bitter glycosides stimulate and increase production of pepsin and hydrochloric acid in the stomach and duodenum, promoting the digestive processes (11). This suits centaury to a sluggish digestion stemming from the stomach, typically causing heartburn, dyspepsia, reflux, and nausea, combining well with meadowsweet (Filipendula ulmaria) and marshmallow (Althaea officinalis). Note that centaury is contraindicated in cases of stomach and gastric ulcers and gastric problems associated with hyperacidity, see the “Safety” section below. The best way to take bitter herbs to support these digestive actions and stimulate the appetite is in a small amount, thirty minutes before a meal (1). In some cases, such as stomach irritation or inflammation, the stimulation of the digestive juices may irritate the stomach, and are better taken with or after food. In cases of nausea, bloating or over-fullness after eating, bitter herbs can be taken to support the digestive processes. As a digestive aid, a few drops of a centaury tincture or an infusion can be sipped following a meal to stimulate and support digestion.

    Liver and gallbladder

    Centaury is a hepatic herb, which refers to a range of actions that aid the functioning of the liver. This is of great importance to any holistic approach, due to the fundamental role the liver has in overall health (4). Some hepatic herbs protect and support the cells within the liver, such as milk thistle. However, the hepatic action of centaury relates to the bitter stimulation of the bile flow from the liver and gallbladder, which helps to clear congestion in those organs. This supports the functioning of the liver so it can more effectively clear toxins from the blood, linking to the alterative action of centaury. Combined with other herbs, centaury can be added to remedies for jaundice, gallstones, and liver congestion (7). For medical conditions such as gallbladder issues and gallstones, it is important to work with a medical herbalist since the size of the stones and the degree of inflammation need to be considered. Bitter herbs may aggravate such conditions by causing the gallbladder to contract, increasing pain, or causing the movement of the stones into the bile duct, risking an obstruction. 

    Bowel 

    Centaury promotes bowel movement by increasing the natural laxative effect of the bile on the intestines, helping to reduce bloating and constipation. Centaury is also useful in cases of poor nutrition and anaemia by supporting the digestive processes and increasing the absorption of nutrients (1). 

    Metabolic

    Centaury is sometimes referred to as an antidiabetic herb (16). The bitter stimulation of the pancreas can help to regulate the secretion of pancreatic hormones and enzymes. This can help with blood glucose regulation after a meal, but requires caution for those taking blood glucose regulating medications (4).

    Centaury (Centaurium erythraea)
    Centaury (Centaurium erythraea)

    Nervous system

    Both acute and chronic stress can suppress the appetite, making bitter herbs like centaury useful during times of stress-induced appetite loss. Similarly, chronic fatigue often results in a reduced appetite  from depression of many biological processes, and limited energy availability for digestion. In these cases, a lack of appetite and the ability to assimilate nutrition can further exacerbate an already depleted state. The actions of centaury throughout the digestive system make it a useful herb during convalescence, or during an illness which results in a diminished appetite. Centaury is also useful as an adjunct in cases of debility or nutrient deficiencies, by supporting the digestive process and increasing the absorption of nutrients (1). Centaury can support the nervous system via this strengthening effect on recovery from illness olong-termrm stress, which can lift the spirits and calm the nerves (7).

    Immune system

    Centaury can support the immune system and help to reduce a fever by opening the channels of elimination to clear heat from the body (1,7). Cooling bitters not only help to reduce a febrile temperature but also stimulate the digestive system to support the removal of infection via the gut (17). The effect of centaury on the digestive system to support appetite and the assimilation of nutrients makes it a valuable herb during convalescence from illness and post-viral syndrome. Also related to supporting the immune system, one of the bitter glycosides, gentiopicrin, also has antimalarial properties (7). The combination of the antimalarial constituents and the support for the febrile state in malaria explains the traditional use of centaury for this condition.

    Musculoskeletal

    Due to the bitter stimulation of the digestive system and the clearing of toxins, centaury can be supportive for the musculoskeletal system (4). Centaury can be added to herbal blends for gout, arthritis and rheumatism (8). 

    Skin

    Centaury can be used both internally and externally for skin eruptions, acne, eczema and boils (8). The internal action is via a cleansing and alterative action (4). Alterative herbs improve the elimination of metabolic waste and are often central to the treatment of skin conditions. Centaury supports both the liver and the bowel with detoxification, which removes the toxin load from the skin as an eliminatory organ, thereby reducing skin eruptions (7). Centaury is anti-inflammatory and antiseptic, and can be applied topically to cuts, grazes, boils and ulcers (7).

  • Research

    Centaury (Centaurium erythraea)
    Centaury (Centaurium erythraea)

    There is lack of contemporary research or published evidence from human clinical trials regarding centaury, although the bitter constituents support the traditional use as an appetite stimulant (9).

    Several laboratory studies have confirmed the bitter constituents in centaury. For example, one study isolated the two secoiridoid glycosides, swertiamarin and sweroside from the aerial parts of Centaurium erythraea (18). The isolated constituents demonstrated antibacterial activity against several bacterial strains, free radical scavenging activities, and low general toxicity (18). 

    The antioxidant activity of an aqueous extract of centaury dried flowering tops has been demonstrated in vitro, via effectively scavenging reactive oxygen species (19). 

    Due to the lack of research from clinical trials, the Committee on Herbal Medicinal Products approves herbal medicine products containing centaury based on its traditional and long-standing use (20). The approval is based on previous evidence from pharmacopoeias, plausible effectiveness, and evidence of safe use for overt 30 years (20). On this basis, HMPC approves centaury to be used for mild indigestion, stomach and gut disorders, and temporary loss of appetite (20).

  • Did you know?

    The name centaury comes from the centaur Chiron (half human, half horse), famous in Greek mythology for his skills in herbal medicine (10,15). He is said to have cured himself with centaury from a wound made with a poisoned arrow (11). For the same reason, centaury is known as the flower of Chiron (7).

Additional information

  • Botanical description

    Centaury is a short and low-growing biennial herb, appearing from April to October, and flowering from June to October (22,23). The height can range from 2–50 cm, and the leaves are mostly in a basal rosette, broad, oblong, narrow at the base and blunted at the end (15,23). The stem leaves are pointed, lance-shaped, growing opposite at distant intervals along the stem (15). The square stem is straight, then branches towards the top, where the flowers develop in clusters (12). The flowers are five-petalled, star-like, clear pink, occasionally white, on short stalks approximately 1cm long (23). The flowers are sensitive to this light and only open in the sun, closing in cool temperatures and at night (12).

  • Common names

    • Common centaury
    • European centaury
    • Red centaury
    • Filwort
    • Christ’s ladder
    • Feverwort
    • Bitter-bloom
    • Bitter herb
    • Lesser centaury
    • Minor centaury
    • Rose-pink
  • Interactions

    Antipeptic medications used for the treatment of heartburn, acid indigestion and peptic ulcers are incompatible with centaury due to opposing therapeutic effects (21). These medications include antacids, gastric acid secretion inhibitors, particularly histamine H2 receptor antagonists such as Zantac (21). Caution is warranted with blood glucose regulating medications, due to the bitter stimulation of the pancreatic hormones which could affect blood glucose balance (4).

  • Contraindications

    Due to the stimulation of acid secretions, centaury is contraindicated when there is stomach irritation or inflammation, gastric problems associated with hyperacidity, and in cases of stomach and gastric ulcers (9,21). 

    Avoid in pregnancy due to the potential for bitter herbs to stimulate uterine contractions, and when breastfeeding due to a lack of data on safety (9,17).

  • Preparations

    • Dried aerial parts (Infusion)
    • Tincture
    • Powdered herb
  • Dosage

    • Infusion: 1–4 g dried herb, in 200 ml boiling water, up to three times per day (9,20)
    • Tincture (1:5 | 45%): 1–2 ml, three times per day (4). Up to 20–40 ml/week (16). A weekly dose of 10–15ml is commonly used in herbal formulas (10)
    • Fluid extract (FE) (1:1): 2–4 ml, 25%, three times per day (9)
    • Powdered herb: 0.25–2 g, up to three times per day (20)
  • Plant parts used

    Aerial parts (stem, leaf, flowers)

  • Constituents

    • Phenolics: Flavonoids, Protocatechuic acid, hydroxybenzoic acid, vanillic acid, syringic acid, p-coumaric acid, ferulic acid, sinapic acid and caffeic acid (9)
    • Alkaloids (secoiridoid): Gentianine, gentianidine, gentioflavine (9,10)
    • Bitter glycosides (monoterpenoids iridoids, and secoiridoid glucosides):  Gentiopicrine (~2%); amarogentrin, centapicrin, gentioflavoside, sweroside and swertiamarin; catapicrin (9,10,11)
    • Phytosterols: Amyrin, erythrodiol, crataegolic acid, oleanolic acid and β-sitosterol (9,10)
    • Xanthones: Eustomin, demethyleustomin (9)
    • Other constituents: Fatty acids, alkanes and waxes (9)
Centaury (Centaurium erythraea)
  • Habitat

    Centaury is Native to UK, Ireland and Europe, growing primarily in the temperate biome (5,22,24). It has been introduced and is widely distributed across USA, South America and Canada (24). It is found in open woods, forests, meadows, shrublands and dry grasslands, often on chalky, nutrient-poor soils and rocky areas, particularly in seasonally damp, sandy depressions (5).

  • Sustainability

    Sustainability status greenThe whole gentian family (Gentiana spp.) is on the United Plant savers “at risk” list due to overharvesting from the wild (2). However, this is a large genus of over 200 species, and centaury is not one of the priority species of concern (2).

    The International Union for Conservation of Nature (IUCN) have globally assessed Centaurium erythraea and listed it as “Least Concern” (5). They state that the species is widespread and abundant throughout Europe, where it is naturalised over a wide area (5). The species is stable and there are currently no major threats reported (5). 

    The Vascular Plant, Red Data List, For Great Britain categorises centaury as least Concern (LC) (25). A taxon is Least Concern when it has been evaluated against the criteria and does not qualify for Critically Endangered, Endangered, Vulnerable or Near Threatened. Widespread and abundant taxa are included in this category (25). Centaury does not appear on the UK Biodiversity Action Plan List of Priority Habitats and Species (26).

    Centaury is not ranked by Nature Serve, and it does not appear on the U.S. Endangered Species act, or the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) (28). 

    Centaury is not listed by CITES (Convention on International Trade in Endangered Species of Wild Fauna and Flora), meaning there are currently no restrictions on trading of the herb (27). 

    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 and 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 very safe to take; however, their safety and efficacy can be jeopardised by quality issues. So, it is important to buy herbal medicines from a reputable supplier, from sources known to test their herbs to ensure there is no contamination, adulteration or substitution with incorrect plant matter, as well as ensuring that recognised marker compounds are at appropriate levels in the herbs.

    Some important quality assurances to look for are certified organic labelling, the correct scientific/botanical name, and the availability of information from the supplier about ingredient origins. A supplier should be able to tell you where the herbs have come from, what contaminants are not in the herb, and what the primary compounds are.

  • How to grow

    Centaury is challenging to cultivate, as it prefers growing in the wild (7). To grow, plant the seeds in June in rich soil or manure, pressing them in lightly and keeping the soil moist (12). As the young plants develop, they may need to be thinned out, and will flower the following year and then self-propagate if the conditions are suitable (12). Centaury is mainly pollinated by bumblebees, and after the flowering period, they produce seed capsules which release tiny seeds that are dispersed by water and wind (2). The whole plant is harvested when in flower and can be dried for later use, remember to leave some flowers to go seed for future species propagation.

  • Recipe

    Centaury wine 

    Adapted from Fischer-Rizzi, Complete Earth Medicine Handbook (12)

    Ingredients

    • 4 tablespoons of centaury herb.
    • 2 tablespoons of bitter orange peel
    • 1 bottle of malaga wine (or other sweet fortified wine)

    Preparation and use

    • Add the centaury and bitter orange peel to a large glass jar and pour over the wine.
    • Ensure all the herb is covered and use a weight if necessary to keep the herbs submerged.
    • Leave to steep for two weeks.
    • Strain and bottle with a tight lid or stopper.
    • To aid digestion, have a small glass before meals.
  • References

    1. Waddell, G. Plant Medicine: A collection of the teachings of herbalists Christopher Hedley and Non Shaw. Aeon; 2023.  
    2. UpS list of herbs & analogs. United Plant Savers. Published May 14, 2021. Accessed November 22, 2024. https://unitedplantsavers.org/ups-list-of-herbs-analogs/ 
    3. Cech, R. The Gentians. United Plant Savers Medicinal Plant Conservation. 2011. https://unitedplantsavers.org/188-gentians/ 
    4. Hoffmann D. Medicinal Herbalism, The Science and Practice of Herbal Medicine. Healing Arts Press; 2003.
    5. Lansdown, R.V. IUCN red list of threatened species 2013: Centaurium erythraea. 11 June 2012. Accessed on 22 November 2024.  https://dx.doi.org/10.2305/IUCN.UK.2013-1.RLTS.T202950A16703434.en
    6. Burton-Seal, J. and Seal, M. The Herbalist Bible: John Parkinson’s Lost Classic Rediscovered. Merline Unwin Books; 2014. 
    7. McIntyre A. Flower Power: flower remedies for healing body and soul through herbalism, homoeopathy, aromatherapy, and flower essences. Henry Holt; 1996. 
    8. Brooke, E. An Astrological Herbal for Women. The Crossing Press, Inc. 1995.
    9. Barnes, J., Anderson, L.A. and Phillipson, J.D. Herbal medicines: a guide for healthcare professionals: Third Edition. Pharmaceutical press; 2007.
    10. Tobyn, G., Denham, A., Whitelegg, M., Kingsbury, S. & Rowling, M. The Western Herbal Tradition: 2000 Years of Medicinal Plant Knowledge: Jessica Kingsley Publishers; 2016.
    11. Mars, B. The Desktop Guide to Herbal Medicine. Basic Health Publications Inc; 2007.
    12. Fischer-Rizzi, S. Complete Earth Medicine Handbook. Sterling Publishing; 1996.
    13. Culpeper, N. Culpepers’ Complete Herbal: a book of natural remedies for ancient ills [1653]. Wordworth Reference; 1995. 
    14. Hool, RL.. Health from British Wild Herbs; 1918. Reprinted on Henritttas Herbpages. Accessed November 22, 2024. https://www.henriettes-herb.com/eclectic/hool/centaury.html 
    15. Grieve M, Leyel CF, Marshall M. A Modern Herbal. the Medicinal, Culinary, Cosmetic and Economic Properties, Cultivation and Folk-Lore of Herbs, Grasses, Fungi, Shrubs & Trees with All Their Modern Scientific Uses [1931]. Dover Publications; 1982. 
    16. Thomsen M. The Phytotherapy Desk Reference: 6th Edition. 6th ed. Aeon Books; 2022. 
    17. Bone K and Mills S. Principles and Practice of Phytotherapy: Modern Herbal Medicine. Elsevier Health Sciences; 2013.
    18. Kumarasamy Y, Nahar L, Cox PJ, Jaspars M, Sarker SD. Bioactivity of secoiridoid glycosides from Centaurium erythraea. Phytomedicine. 2003;10(4):344-7. https://doi.org/10.1078/094471103322004857 
    19. Valentão P, Fernandes E, Carvalho F, Andrade PB, Seabra RM, Bastos ML. Hydroxyl radical and hypochlorous acid scavenging activity of small centaury (Centaurium erythraea) infusion. A comparative study with green tea (Camellia sinensis). Phytomedicine. 2003;10(6-7):517-22. https://doi.org/10.1078/094471103322331485 
    20. European Committee on Herbal Medicine Products (HMPC). Centaurii herba – herbal medicinal product: Centaury. European Medicines Agency. Accessed: 30 November, 2024. https://www.ema.europa.eu/en/medicines/herbal/centaurii-herba 
    21. Brinker, FJ. Herbal Contraindications & Drug Interactions: Plus Herbal Adjuncts with Medicines. Eclectic Medical Publications, 2010.
    22. Rich, TCG., Stroh, PA., Humphrey, TA., Burkmar, RJ., Pescott, OL., Roy, DB., & Walker, KJ. Centaurium erythraea Rafn. BSBI Online Plant Atlas. Published 2020. Accessed November 22 2024. https://plantatlas2020.org/atlas/2cd4p9h.q88  
    23. Blamey M, Fitter R, Fitter AH. Wild Flowers of Britain and Ireland: 2Nd Edition. A & C Black; 2013.
    24. Royal Botanical Gardens Kew (RBGK). Centaurium erythraea Rafn. Plants of the Word Online (POWO). Accessed November 22, 2024. https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:326619-2 
    25. Cheffings C, Farrell L, (eds), Dines, T.D., Jones, R.A., Leach, S.J., McKean, D.R., Pearman, D.A., Preston, C.D., Rumsey, F.J., Taylor, I. The Vascular Plant Red Data List for Great Britain. Species Status No. 7. Joint National Conservation Committee. 2005. https://hub.jncc.gov.uk/assets/cc1e96f8-b105-4dd0-bd87-4a4f60449907
    26. UK Biodiversity Action Plan List of Priority Habitats and Species (2010) https://data.jncc.gov.uk/data/bdd8ad64-c247-4b69-ab33-19c2e0d63736/UKBAP-UKListPriorityHabitatsSpecies-V1.4-2010.xls
    27. Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES). Accessed November 22, 2024. https://checklist.cites.org/#/en 
    28. NatureServe explorer 2.0. Natureserve.org. Centaurium erythraea: Common Centaury, Published: 11/1/2024.  Accessed November 22, 2024. https://explorer.natureserve.org/Taxon/ELEMENT_GLOBAL.2.155870/Centaurium_erythraea 
Aromatic
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
The astringent 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.
Bitter
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.
Cooling
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.
Hot
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..
Mucilaginous
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..
Pungent
The pungent flavour refers to the powerful taste of hot spices including mustard (Brassica spp.), ginger (Zingiber officinale), horseradish (Amoracia rusticana), chilli (Capsicum spp.), and garlic (Allium sativum). These herbs act to enliven and invigorate the senses, and they often also have heating qualities. Unlike other tastes, the effect is not linked to a specific receptor on the tongue and instead acts through direct irritation of tissues and nerve endings. Energetically, pungent herbs are known to disperse energy (qi) throughout the body. Pharmacologically, pungent herbs dry excess moisture and mucus, as well as stimulate digestion and metabolism.
Resinous
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!
Salty
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'.
Sharpness
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.
Sour
The sour taste occurs because of the stimulation of hydrogen ions which trigger the sour taste receptors on the tongue. The more acidic a substance, the more hydrogen ions will be released. The sour taste comes from acidic substances including citrus, fermented foods, tannins, and vinegars. Sour foods and herbs absorb excess moisture, whilst also increasing the production of saliva. Energetically, sour substances tonify the lungs, playing a role in disease prevention. Excessive use, however, can result in malabsorption of nutrients. Examples of sour herbs include, rosehips (Rosa canina), raspberry (Rubus idaeus), rhubarb (Rheum palmatum), schisandra (Schisandra chinensis), hawthorn (Crataegus monogyna) and ginkgo (Ginkgo biloba).
Sweet
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.
Umami
The umami taste was originally discovered in 1985 in Japan and is directly translated from the Japanese as a ‘pleasant savoury taste’. It is referred to as the ‘fifth taste’ and is a salty, rich, and meaty flavour. The umami flavour is produced by amino acids (glutamic acid and aspartic acid) found in many food and plant sources including tomatoes, mushrooms, seaweeds and soy-based foods. Umami foods can improve nutritional absorption and digestion as there are also umami receptors in the gut as well as the mouth. Examples of umami herbs include green tea (Camellia sinensis), reishi (Ganoderma lucidum), nettle (Urtica dioica), cordyceps (Ophiocordyceps sinensis), shitake (Lentinula edodes) and bladderwrack (Fucus vesiculosus).

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