A voice for
herbal medicine

We share traditional, scientific and practical insights written by experienced herbalists and health experts from the world of herbal medicine and natural health

  • Herb overview

    Safety

    Generally considered safe but has been associated with some occasional side effects

    Sustainability

    Status:
    Vulnerable

    Key constituents

    Berberine
    Coptisine
    Palmatine
    Jatrorrhizine

    Quality

    Origin: China
    Cultivated

    Key actions

    Clears heat
    Drains damp
    Sedates fire
    Resolves toxicity

    Key indications

    Dysentery
    Fever
    Inflammation
    Diabetes

    Key energetics

    Bitter
    Cold

    Preperation and dosage

    Rhizome
    1.5–9 g/per day
    Decoction

  • How does it feel?

    Huang lian is very cold, very bitter and drying.

    Huang lian (Coptis chinensis)
    Huang lian (Coptis chinensis)
    Huang lian (Coptis chinensis)

  • Into the heart of huang lian

    Huang lian is one of the coldest and most bitter herbs in the Chinese pharmacopoeia. It even appears in the popular idiom, “a mute person eating huang lian,” referring to being forced to suffer in silence (4). However, another saying says: “good medicine tastes bitter,” meaning that good advice can be uncomfortable to hear (5), but also attests literally to the esteem in which the therapeutic potential of huang lian is held.

    The Yellow Emperor’s Inner Classic says that the bitter taste drains and dries while cold overcomes heat (6), properties which give this herb its exceptional fire draining and damp drying properties. This is also behind its limitations, which state that it should not be used in either yin or yang deficiency, because its drying nature will harm the yin, while its cold, descending properties will harm the yang.

    The Spleen and Stomach also favour warm, dry conditions meaning, despite it promoting dryness, the coldness of this herb readily damages the digestive system (1). It should also be used cautiously in qi and blood deficiency (7).

  • What practitioners say

    Digestive systemDigestive system

    The dominant use of huang lian is in treating inflammation and infection of the gastrointestinal system where its potent antibacterial and anti-inflammatory properties are able to be employed to its fullest extent, without being hampered by the poor bioavailability of berberine which is often less than 1% (8).

    It may be combined with a number of other herbs to direct its action towards specific areas of digestive heat. For example, in instances of constipation with fever, flushed face and red eyes, it is combined with Baikal skullcap (Scutellaria baicalensis) and rhubarb root (Rheum officinale) in xie xin tang, which is the basis for a whole family of formulas in which huang lian is the only herb consistently present, including:

    • Where there is dysentery with blood and mucus in the stool, it is combined with mu xiang (Aucklandia lappa) in Xiang Lian Wan
    • In vomiting, reflux and gastritis it is combined with wu zhu yu (Evodia rutaecarpa) in Zuo Jin Wan (9)
    • While in nausea it is combined with zi su ye (Perilla frutescens) leaf in Su He Huang Lian Tang (10)

    This may also be the mechanism by which huang lian is able to act on so many other systems due to the close relationship of the gut to the brain, skin, endocrine and immune systems (11).

    Immune system

    Huang lian is known for its ability to bring down fevers and reduce inflammation both topically and systemically (1,7). The use of this herb for treating fevers dates back to the earliest medical writings in the Han dynasty but its intense cold and bitter qualities made it an important part of the Warm Disease School of the Qing dynasty.

    It takes a prominent place in formulas such as Clear the Nutritive Level Decoction (Qing Ying Tang) where it clear heat from the qi and ying levels with high fever that worsens at night, severe irritability and restlessness, possibly with insomnia and delirium. It also appears in Clear Epidemics and Overcome Toxicity Drink (Qing Wen Bai Du Yin) and Guide Out the Red and Order the Qi Decoction (Dao Chi Cheng Qi Tang) that address heat in the blood level due to its ability to treat bleeding, rashes and delirium.

    The ability of huang lian to affect the immune system suggests it may have much further indications that just fevers. It has also been suggested to be of use in inflammatory conditions such as arthritis, including rheumatoid, gouty and osteoarthritis (12). In traditional terms, rheumatoid and gouty arthritis translate to damp-heat channel obstructions and often have a dietary component making huang lian an obvious choice.

    In treating osteoarthritis, it is important to differentiate between this damp-heat pattern with red, swollen joints that do not respond well to heat, and the more common cold-damp obstruction that tends to be less inflamed but present with greater stiffness and does respond well to heat.

    Endocrine system

    Berberine has been investigated recently in the management of diabetes for its ability to control blood sugar levels without interacting with medication (2,3). This has precedents in older literature too, with the classical understanding of diabetes, called “wasting and thirsting (xiao ke)” in ancient Chinese literature, being described as three increases (thirst, appetite and urination) and one loss (weight) (13).

    Huang lian played a role in some formulas to address the Stomach heat that leads to a large appetite and thirst, but it needed to be combined with other herbs that stop the loss of fluids through the urine and nurture the yin damaged by the heat. Even then, many classical authors warned that all treatments were futile if the patient did not moderate their diet and lifestyle.

    Nervous system

    By altering the gut microbiome, huang lian is able to affect the heart (14) and brain (15). This may explain how huang lian has the ability to drain fire from the Heart and is used in some formulas for calming the spirit. 

    In the Grand Communication Pill (Jiao Tai Wan), huang lian is combined with a small dose of cinnamon (Cinnamomum spp.) to treat insomnia, irritability, restlessness and continuous palpitations with cool limbs (9). This is said to be because there is disharmony between the Heart and Kidneys, the shaoyin axis of fire and water, with fire lacking a basis in the Kidney yang and instead rising upwards towards the Heart, agitating the spirit. Huang lian clears the excess heat from the Heart and makes it descend, while cinnamon helps to guide it back to the Kidneys.

    Huang lian is also appended to formulas that treat mental disturbances to address cases of more severe heat. For example, in Huang Lian Wen Dan Tang it is added to the formula Wen Dan tTng that already treats phlegm-heat harassing the Heart due Gallbladder and Stomach disharmony obstructing the qi dynamic (9). This increases its action on restlessness and irritability, especially if accompanied by an intense bitter taste in the mouth.

    Skin health

    Huang lian can treat skin conditions both topically, where its antimicrobial abilities can be employed on the skin directly, and taken internally where it can reshape the gut microbiome whose disruption is correlated with a number of skin conditions (16).

    Its cold and drying nature mean that it excels at treating hot, swollen sores that may emit pus, but it should be avoided in cases where the skin is dry or cool. A common preparation for damp-heat skin conditions is to mix finely powdered huang lian with a base ointment such as petroleum jelly (17). 

    Eye health

    A traditional use that is mentioned only as a side note, if at all, in most modern pharmacopoeias, is for eye disorders, but this appears to have been an important use in ancient times. The earliest Chinese pharmacopoeia, the Divine Farmer’s Materia Medica, says it treats “eye pain, damage to the corner of the eye, and tearing; [and] brightens the eyes” (18).

    Meanwhile, the 15th century (Ming dynasty) Essential Subtleties on the Silver Sea records a decoction of huang lian used to wash the eyes to counter an epidemic eye infection (19). This use continues today with research suggesting huang lian combined with levofloxacin can reduce eyelid swelling and pain, shorten healing time and improve treatment success rates (20).

  • Huang lian research

    The clinical efficacy of Gegen Qinlian Decoction in treating type 2 diabetes is Positively correlated with the dose of Coptidis rhizoma: Three randomized, doubleblind, dose-parallel controlled clinical trials

    Huang lian (Coptis chinensis)
    Huang lian (Coptis chinensis)

    Kang et al. (21) set out to investigate whether huang lian or ge gen (Puerariae lobatae radix) was the active ingredient in regulating blood sugars in patients with type 2 diabetes treated with a formula that contained both.

    This study followed up a previous study in which they demonstrated the effect on this formula against a placebo group, so this study did not use placebo controls but compared the two treatment groups of 120 participants each, consisting of new-onset type 2 diabetes patients diagnosed with a damp-heat TCM pattern, aged 30–65 years, who completed a screening period consisting of diet control and exercise for two weeks, and still had HbA1c ≥7.0%, fasting blood glucose between 7.0–13.9 mmol/L or two hours postprandial blood glucose ≥11.1mmol.

    These were randomly divided into three arms in each group (six groups of ~40 participants each), all receiving the entire formula over a course of 12 weeks but with either high, medium and low doses of either herb. The standard formula consisted of Puerariae lobatae radix 72 g, Scutellariae radix 27 g, Coptidis rhizoma 27 g and Glycyrrhizae radix et rhizoma 18 g. The group receiving a low dose of Pueraria Lobata received 24g and the high dose received 120 g, while the group receiving a low dose of Coptis chinensis received 9g and the high dose received 45 g. 

    The primary outcome measurement was changes in HbA1c relative to baseline, while secondary outcome measurements were: fasting blood glucose and two hour post-load glucose; blood lipids, including:

    • Cholesterol, triglyceride, high-density lipoprotein (HDL), and low-density lipoprotein (LDL)
    • Weight, body mass index (BMI), waist circumference, hip circumference, and waist-hip ratio
    • Fasting insulin, Homeostasis Model Assessment-β, Homeostasis Model Assessment of Insulin Sensitivity, and Homeostasis Model Assessment of Insulin Resistance
    • A total symptom score

    HbA1c  and fasting insulin were taken at 0 and 12 weeks. All other measurements were taken at 0, 4, 8 and 12 weeks.

    The results showed that the change in HbA1c was not significantly correlated with the dose of Puerariae lobatae radix but did positively correlate with the dosage of Coptidis rhizoma (p<0.0492). Neither herb showed a significant correlation with two hour post-load glucose tests.

    Secondary outcomes were discussed in supplementary material. This implies that Coptis chinensis is the main agent that reduced HbA1c but the authors acknowledge that the limited number of participants mean the effect size is small and could have benefitted from larger groups, placebo arms, and longer duration of treatment to make better conclusions.

    Efficacy and safety of mixture of ivy leaf extract and Coptidis rhizome in the treatment of acute bronchitis: Multicenter, randomized, double-blinded, active-controlled, parallel, therapeutic confirmatory clinical trial

    Han et al. (22) investigated the safety and effectiveness of huang lian, mixed with ivy leaf (Hedera helix) extract in a syrup, compared against Pelargonium sidoides in the treatment of acute bronchitis. P. sidoides was chosen as an active comparison because it has been demonstrated to be effective against placebo in several trials with varying levels of approval in systematic analyses and meta-analyses (23,24).

    The study recruited 220 participants from 13 treatment centres in Korea, all aged 19-75 years old with symptoms of acute bronchitis scoring five points or more on the Bronchitis Severity Score (BSS), with symptom duration less two weeks and presenting without fever.

    They were treated with either intervention three times per day for seven days, after they underwent efficacy and safety assessments, measured as changes in BSS, physician assessed treatment response, overall improvement, and subjective satisfaction using the Integrative Medicine Outcomes Scale. Safety was assessed by asking to report adverse events.

    The results indicated that there was no significant difference between the two arms, suggesting that huang lian and ivy leaf extract were equally effective at reducing bronchitis. This is important because P. sidoides has already demonstrated efficacy. It was suspected to be due to α-hederin from ivy leaf which reduces bronchospasms and berberine from Coptis which is anti-inflammatory, although one limitation of this study is that it cannot determine if both were contributing to this effect.

    Berberine versus placebo for the prevention of recurrence of colorectal adenoma: a multicentre, double-blinded, randomised controlled study

    Chen et al. (25) explored the possibility that berberine could have chemopreventive activity against colorectal adenoma. 1136 Chinese participants from across six provinces aged 18–75 years who had between one and six histologically confirmed colorectal adenomas removed within the last 6 months were recruited and randomly assigned to receive 0.3 g berberine twice daily or placebo. Outcomes were measured with colonoscopy one and two years after enrolment to determine the rate of recurrence.

    Among 895 who completed the study, the active arm had a 36% recurrence rate of colorectal adenomas, compared to 47% in the placebo arm (p<0.001), with no cancers detected during follow-up. The implications were that berberine significantly decreased the recurrence rate of colorectal adenoma and all polypoid lesions.

    No serious adverse events were reported. Furthermore, a follow up study (26) of 781 of the original participants found that the protective effects of berberine persisted for at least 6 years after the treatment ended, with lower adenoma recurrence rate (34.7% vs. 52.1%; p<0.001) and lower neoplasm occurrence rate (63.4% vs. 71.0% p<0.004). 

  • Historical use of huang lian

    Huang lian (Coptis chinensis)
    Huang lian (Coptis chinensis)

    Huang lian can be used is whenever there is damp-heat in the stomach and intestines manifesting as diarrhoea or dysentery that may or may not contain pus and blood, a burning sensation in the anus after defecation, foul smelling stools tenesmus, feelings of incomplete evacuation, abdominal pain, epigastric distension and fullness, vomiting or nausea, burning gastric pain, acid reflux, inflamed or bleeding gums and thirst with no desire to drink or a preference for cold drinks (1).

    This will be accompanied by other damp-heat signs such as a rapid, slippery pulse and a red tongue with a greasy, yellow coating. It will generally be combined with other herbs that help to direct its actions depending on the specific presentation.

    A second common use is to sedate fire and resolve toxicity. This generally relates to the Liver or Heart fire blazing with symptoms such as high fever, irritability, insomnia, dry mouth and throat, a red face, nosebleeds or vomiting blood and dark, scanty urine (7). Liver fire will also present with dizziness, headache, red eyes, short temper, nightmares, tinnitus, and constipation while Heart fire will manifest with tongue ulcers and mania (1).

    Both will have a rapid pulse and red tongue, but the redness Heart fire tends to be localised to the tip, while the Liver is around the sides. Again, it will be combined with different herbs to direct its effects.

    The last traditional use of huang lian is for topical application for conditions arising from toxic fire. This includes abscesses, lesions, carbuncles, furuncles, burns, and any red, hot and swollen areas of inflammation where it can be applied as a powder (1).  It can also be used as a wash for red and painful eyes, or ulcerations of the tongue and mouth (7).

  • Huang lian’s herbal 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.

    Western actions

    Chinese actions

  • Huang lian’s energetic qualities

    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 can I use huang lian for?

    Due to its high content of antimicrobial and anti-inflammatory berberine, huang lian can be used for a number of conditions that would be considered inflammatory or infectious. It is most effective for gastrointestinal infection due to the poor absorption and short half-life of berberine, making it most useful in the treatment of gastritis, stomach ulcers and infectious diarrhoea or dysentery (1).

    It has also demonstrated some antiviral activities, which mean that it is often used in the treatment of influenza and hepatitis, and some antifungal actions that help with dermatological conditions where it can be applied topically.

    Recent interest around the use of berberine in the management of blood glucose in type 2 diabetes (2), has also led to researchers investigating huang lian (3). This potential novel usage shows promise but further research is required.

  • Did you know?

    The deep orange colour of the roots has led to huang lian being used by indigenous Bai peoples of Yunnan as a yellow dye for textiles (27,28).

  • Botanical description

    Coptis chinensis Franch. is an evergreen perennial herb 15–25 cm tall with 3–6 branched and nodular rhizomes with short stolon internodes that are bright golden-yellow internally (29).

    It is in leaf all year, flowers from February to March, and the seeds ripen from April to May.

    It is hermaphrodite and is pollinated by insects (28).

  • Common names

    Chinese goldenthread

  • Habitat

    Huang lian grows in China and East Asia in damp coniferous woods and bogs, or forests, shaded places in valleys at elevations of 500–2000 m (28).

  • How to grow huang lian

    Huang lian succeeds in a light, moist, humus-rich, slightly acidic soil with a northerly aspect or light shade (28). Plants are hardy to at least –15°C.

  • Herbal preparation of huang lian

    • Unprocessed: Stronger at clearing heat, sedating fire and draining dampness (1)
    • Dry fried: Moderates its coldness to prevent injury to the yang qi of the Stomach and Spleen (7)
    • Wine fried: Directs its actions towards the head and eyes (7) while also reducing the effects of its bitter and cold properties (1)
    • Ginger fried: Focuses its actions on the Stomach and directs qi downwards to aid with nausea (7), while also reducing the effects of its bitter and cold properties (1)
    • Evodia fried: Directs its activities towards the Liver, alleviating diarrhoea, nausea and acid regurgitation (7)
    • Salt fried: Reduces its drying properties and directs its actions towards the lower body (7)
    • Charred: Guides its effects to the Blood level to stop haemorrhage due to heat, especially in the treatment of dysenteric disorders with blood in the stool (7)
    • Fried with pig bile: Enhances its effects on clearing heat from the Liver and Gallbladder (1)

  • Plant parts used

    Rhizome

  • Dosage

    • Tincture (1:3 | 25%)  (29,30)
    • Infusion/decoction: 1.5–0 g, occasionally up to 15 g (1,7)
    • Topically as a powder (1)

  • Constituents

    • Alkaloids: Berberine, coptisine, palmatine, jatrorrhizine, columbamine, worenine, magnoflorine

  • Huang lian recipe

    Huang Lian Jie Du Tang (Coptis decoction to resolve toxicity)

    This is the representative formula for resolving damp-heat and fire toxicity anywhere in the body and is used as the basis for a number of other formulas that add or subtract herbs in order to direct its focus onto a specific system.

    It consists of four herbs, three of them known as the “three yellows” which each drain damp-heat but focus their effect on one of the “Three Burners” (body regions): upper, middle and lower, with the final herb, gardenia, having the property of draining heat from all three (32).

    Coptis plays the role of the title herb in this formula because it is the most bitter, cold and draining of them all. It was originally developed for the treatment of alcohol abuse whose effects can be felt all over the body with signs of insomnia, flushes, irritability and distention that can provide useful clinical markers for its use (9).

    Ingredients

    • 9 g Coptidis rhizoma (huang lian) — often reduced to ⅓  or ½ in modern prescriptions
    • 6 g Scutellariae radix (huang qin)
    • 6 g Phellodendron cortex (huang bai)
    • 6–12 g (14 pieces) Gardeniae fructus (zhi zi) — opened
    • 1200 mL water

    How to make a huang lian decoction

    • Cook the ingredients in 1200 mL of water until 400 mL remains (32).
    • Remove the dregs.
    • Optional: Some texts advise allowing to cool to enhance its cooling effects.
    • Divide into two equal doses and take over the course of one day.
Chronic inflammation: The role of sugar

Chronic inflammation: The role of sugar

  • Safety

    Huang lian is generally considered safe but has been associated with some occasional side effects including transient diarrhoea, abdominal distention, borborygmus, increased urination, loss of appetite, nausea, vomiting, epigastric discomfort (7), allergic rashes, dizziness, tinnitus, headache, palpitations and low red blood cell count (1).

    In infants, it has been known to cause jaundice (7).

  • Interactions

    Huang lian inhibits cytochrome P450 enzymes 2D6, 2C9, and 3A4, and can also induce 3A4 with prolonged use, although the clinical significance of these interactions is not known (33).

    Berberine has also shown promise as a protective agent against cyclophosphamide induced nephrotoxicity (34), although only animal trials have been conducted to date.

  • Contraindications

    Traditional contraindications include any deficiency disorders, especially heat from deficient yin, or cold from deficient yang, Spleen and Stomach deficiency and qi and blood deficiency (7). 

    Modern contraindications include jaundiced neonates, due to it displacing bilirubin, and that caution is applied with patients with heart disease because it may prolong QTc intervals (33).

  • Sustainability status of huang lian

    Coptis chinensis is classified as vulnerable by the IUCN, with other species such as C. deltoidea and C. teeta that are also used as medicinal species being critically endangered and endangered, respectively (31,35) from to over-harvesting and a habitat that is shrinking due to climate change (36).

    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

    Huang lian is almost exclusively harvested from cultivated crops grown in the Chinese provinces of Chongqing, Gansu, Guizhou, Hubei, Saanxi and Sichuan with good agricultural practice standards awarded at several of these sites (31).

    Good quality is supposed to be thick, strong and firm with a reddish-yellow fractured surface, no remnants of stems and hairy rootlets, and missing the long thin portion of the rhizome that is found between the nodes, referred to as “crossing the bridge” (37).

    Three species are accepted and can be recognised by these distinguishing features (37): C. chinensis (wei lian) gathers in a cluster with a shape like a chicken claw, is 3–6 cm in length and 0.3–0.8 cm in diameter; C. deltoidea (ya lian) is generally single rhizomes, slightly crooked and larger, at 4–8 cm in length and 0.5–1 cm in diameter; while C. teeta (yun lian) is also generally single rhizomes that are curved with ridges and relatively thin and small. C. japonica has also been brought into use in Japan as an additional local source (31).

    Good quality should be assayed to have no less than 4.2% berberine content on extraction (38).

  • References

    1. Chen JK, Chen T. Chinese Medical Herbology and Pharmacology. City of Industry, CA: Art of Medicine Press; 2008.
    2. Xie W, Su F, Wang G, et al. Glucose-lowering effect of berberine on type 2 diabetes: a systematic review and meta-analysis. Front Pharmacol. 2022;13:1015045.  https://doi.org/10.3389/fphar.2022.1015045
    3. Pan L, Zhai X, Duan Z, Xu K, Liu G. Systematic review and meta-analysis of Coptis chinensis Franch.-containing traditional Chinese medicine as an adjunct therapy to metformin in the treatment of type 2 diabetes mellitus. Front Pharmacol. 2022;13:956313. https://doi.org/10.3389/fphar.2022.956313
    4. 啞巴吃黃連. Wiktionary. Published 2023. Accessed April 16, 2026.  https://en.wiktionary.org/wiki/啞巴吃黃連
    5. 良藥苦口. Wiktionary. Published 2022. Accessed April 16, 2026. https://en.wiktionary.org/wiki/良藥苦口
    6. Unschuld PU, Tessenow H. Huang Di Nei Jing Su Wen: An Annotated Translation of Huang Di’s Inner Classic – Basic Questions. Berkeley, CA: University of California Press; 2011.
    7. Bensky D, Clavey S, Stoger E. Chinese Herbal Medicine: Materia Medica. 3rd ed. Seattle, WA: Eastland Press; 2004.
    8. Habtemariam S. The quest to enhance the efficacy of berberine for type-2 diabetes and associated diseases: physicochemical modification approaches. Biomedicines. 2020;8(4):90. https://doi.org/10.3390/biomedicines8040090
    9. Scheid V, Bensky D, Ellis A, Barolet R. Chinese Herbal Medicine: Formulas and Strategies. 2nd ed. Seattle, WA: Eastland Press; 2009.
    10. Wang SX. Warp and Weft of Warm Diseases 溫熱經緯. 1852. Accessed April 18, 2026. https://ctext.org/wiki.pl?if=gb&res=660431
    11. Afzaal M, Saeed F, Shah YA, et al. Human gut microbiota in health and disease: unveiling the relationship. Front Microbiol. 2022;13:999001. https://doi.org/10.3389/fmicb.2022.999001
    12. Li M, Tian F, Guo J, et al. Therapeutic potential of Coptis chinensis for arthritis with underlying mechanisms. Front Pharmacol. 2023;14:1243820. https://doi.org/10.3389/fphar.2023.1243820
    13. Shen XT. The milestones of diabetes in traditional Chinese medicine. Sun Ten J. 2007;8:51-54. Accessed April 18, 2026. https://www.suntenglobal.com/_en/News-Datain.php?id=475
    14. Wen S, Liu X, Liu L, Hu Y, Zhang Q. Landscape of berberine targets: a potential pharmacological insight for heart failure treatment. J Cardiovasc Pharmacol. 2025;86(5):420-434. https://doi.org/10.1097/FJC.0000000000001750
    15. Chen CY, Zhang Y. Berberine: an isoquinoline alkaloid targeting the oxidative stress and gut-brain axis in the models of depression. Eur J Med Chem. 2025;290:117475. https://doi.org/10.1016/j.ejmech.2025.117475
    16. Zhao Y, Yu C, Zhang J, Yao Q, Zhu X, Zhou X. The gut-skin axis: emerging insights in understanding and treating skin diseases through gut microbiome modulation (review). Int J Mol Med. 2025;56(6):210. https://doi.org/10.3892/ijmm.2025.5651
    17. Xu Y. Dermatology in Traditional Chinese Medicine. Yi S, trans. China: Donica Publishing Ltd; 2004.
    18. Wilms S, trans. The Divine Farmer’s Classic of Materia Medica. Corbett, OR: Happy Goat Productions.
    19. Kovacs J, Unschuld PU. Essential Subtleties on the Silver Sea. Berkeley, CA: University of California Press.
    20. Wang QM, Ma YP, Zhang P, Zhang X, Gong HX, Pang YJ. Clinical application of traditional Chinese medicine eye coating agents in the treatment of hordeola. Srp Arh Celok Lek. 2025;153(1-2):59-65. https://doi.org/10.2298/sarh240712009w
    21. Kang X, Jin D, Ji H, et al. The clinical efficacy of Gegen Qinlian decoction in treating type 2 diabetes is positively correlated with the dose of Coptidis rhizoma: three randomized, double-blind, dose-parallel controlled clinical trials. Drug Des Devel Ther. 2024;18:5573-5582. https://doi.org/10.2147/DDDT.S487315
    22. Han KI, Kim TH, Ra SW, et al. Efficacy and safety of mixture of ivy leaf extract and Coptidis rhizoma in the treatment of acute bronchitis: multicenter, randomized, double-blinded, active-controlled, parallel, therapeutic confirmatory clinical trial. Curr Med Res Opin. 2024;40(7):1235-1243. https://doi.org/10.1080/03007995.2024.2362273
    23. Agbabiaka TB, Guo R, Ernst E. Pelargonium sidoides for acute bronchitis: a systematic review and meta-analysis. Phytomedicine. 2008;15(5):378-385. https://doi.org/10.1016/j.phymed.2007.11.023
    24. Timmer A, Günther J, Motschall E, Rücker G, Antes G, Kern WV. Pelargonium sidoides extract for treating acute respiratory tract infections. Cochrane Database Syst Rev. 2013;2013(10):CD006323. https://doi.org/10.1002/14651858.CD006323.pub3
    25. Chen YX, Gao QY, Zou TH, et al. Berberine versus placebo for the prevention of recurrence of colorectal adenoma: a multicentre, double-blinded, randomised controlled study. Lancet Gastroenterol Hepatol. 2020;5(3):267-275. https://doi.org/10.1016/S2468-1253(19)30409-1
    26. Tan YJ, Zou TH, Yu K, et al. Berberine for preventing colorectal adenoma recurrence and neoplasm occurrence: 6-year follow-up of a randomized clinical trial. Cell Rep Med. 2025;6(9):102293. https://doi.org/10.1016/j.xcrm.2025.102293
    27. Fan Y, Zhao Y, Liu A, et al. Indigenous knowledge of dye-yielding plants among Bai communities in Dali, Northwest Yunnan, China. J Ethnobiol Ethnomed. 2018;14(1):74. https://doi.org/10.1186/s13002-018-0274-z
    28. Plants For A Future. Coptis chinensis – Huang Lian. PFAF Plant Database. Published 2025. Accessed April 19, 2026. https://pfaf.org/user/Plant.aspx?LatinName=Coptis+chinensis
    29. Bristol Botanicals. Huang Lian tincture – Coptis chinensis. Accessed April 16, 2026. https://www.bristolbotanicals.co.uk/pr-979
    30. Herbal Apothecary. Coptis chinensis / Huang Lian / 1:3 25%. Accessed April 16, 2026. https://herbalapothecaryuk.com/products/coptis-chinensis-huang-lian-13-25
    31. Leon C, Lin YL. Chinese Medicinal Plants, Herbal Drugs and Substitutes: An Identification Guide. Kew, UK: Kew Publishing; 2017.
    32. Chen JK, Chen T. Chinese Herbal Formulas and Applications: Pharmacological Effects and Clinical Research. City of Industry, CA: Art of Medicine Press; 2015.
    33. Memorial Sloan Kettering Cancer Center. Huanglian. Accessed April 16, 2026. https://www.mskcc.org/cancer-care/integrative-medicine/herbs/huanglian
    34. Mombeini MA, Kalantar H, Sadeghi E, Goudarzi M, Khalili H, Kalantar M. Protective effects of berberine as a natural antioxidant and anti-inflammatory agent against nephrotoxicity induced by cyclophosphamide in mice. Naunyn Schmiedebergs Arch Pharmacol. 2022;395(2):187-194. https://doi.org/10.1007/s00210-021-02182-3
    35. Li J, Fan G, He Y. Predicting the current and future distribution of three Coptis herbs in China under climate change conditions, using the MaxEnt model and chemical analysis. Sci Total Environ. 2020;698:134141. https://doi.org/10.1016/j.scitotenv.2019.134141
    36. Zhao Q, Zhang Y, Li WN, Hu BW, Zou JB, Wang SQ, Niu JF, Wang ZZ. Predicting the potential distribution of perennial plant Coptis chinensis Franch. in China under multiple climate change scenarios. Forests. 2021;12(11):1464. https://doi.org/10.3390/f12111464
    37. Zhao Z, Chen H. Chinese Medicinal Identification: An Illustrated Approach. Taos, NM: Paradigm Publications; 2014.
    38. Taiwan Herbal Pharmacopeia. 4th ed. English version. Taipei: Ministry of Health and Welfare; 2022.

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Steve Woodley
- Researcher, Chinese herbalist, Lecturer

Steve Woodley is a practitioner, writer, researcher and teacher of Chinese medicine with a specialist interest in how traditional, natural healing techniques influence our metabolism.

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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 (e.g. 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.
Bland
Blandness refers to a mild, plain, non-stimulating taste and an energetic action that neither irritates nor strongly activates physiological processes. In traditional Chinese medicine, bland substances gently drain dampness and promote urination, relieving excess fluid whilst also preserving qi and yin. Western traditional medicine similarly associates healing with bland substances that avoid extremes of heat or cold and promote restoration of balance. Blandness signifies regulation by supporting elimination and normal tissue function without forceful stimulation, helping to create a gentle and balanced state of homeostasis.
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, horseradish 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.
Neutral
Neutral herbs are characterised as by balanced temperature and energetics — neither warming nor cooling, nor strongly dispersing nor consolidating, and are, therefore, used across a wide spectrum of constitutional and pathological states. In Chinese medicine, this level, calm quality supports the centre, and gently strengthens digestion, regulates fluids, and resolves damp without provoking too much heat or cold. In Western medicine, neutral herbs are regarded as equal in relation to hot/cold or damp/dry and capable of maintaining a state of equilibrium. Neutral herbs can be seen as moderating reactivity, and supporting homeostasis rather than forcing change.
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'.
Sharp
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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