What Long Dan Xie Gan Tang is for
The skin picture is hot, red and often wet: a band-like eruption on a red base, redness and itching in the genital area, or weeping eczema that feels hot to the touch. The explanation is Fire with Dampness in the Liver and Gallbladder, and the formula drains both downward so the lesions lose their fuel. It is short term, because the herbs are intensely bitter and cold.
Three skin pictures carry this pattern. One is a band-like eruption on a red base that burns rather than itches. Another is redness and itching around the genitals, sometimes with discharge. The third is eczema that is red, wet and hot rather than dry and scaly. What they share is heat in the lesion, a deeper red than ordinary inflammation, and moisture that keeps returning. The skin looks angry, and the person often feels the heat of it.
The Liver and Gallbladder channels reach the sides of the body and the genital area, which is why one pattern can show at either end. Long Dan Cao, Huang Qin and Zhi Zi form the cooling core that drains the Fire; Ze Xie, Mu Tong and Che Qian Zi open a downward route so the Dampness leaves the tissue instead of staying in it; Chai Hu carries the formula into those channels. Sheng Di Huang, Dang Gui and Gan Cao protect the Blood, the Yin and the digestion from so much bitter cold, which is what makes a short course tolerable.
Because it is cold and draining, it is used for a limited time, usually three to seven days, and only where the skin is genuinely hot and damp. Pale, dry or cold skin is the wrong picture, and cold, weak digestion is excluded because the bitterness would damage it further. Redness that comes from deficient Yin rising is not excess Fire either, and draining would leave that person weaker.
Actions
- Drains excess Fire from the Liver and Gallbladder
- Clears Damp-Heat from the Liver channel
- Drains Damp-Heat downward through the urine
- Cools the Blood and protects the Yin while doing so
Properties
- Taste and temperature: Predominantly bitter and cold, with a mild sweet and bland undertone. The bitter quality drains Fire and dries Dampness; the bland quality promotes urination so the Dampness has an exit.
- Organs: Liver, Gallbladder, Urinary Bladder, Small Intestine
- Channels: Liver, Gallbladder, Bladder, Small Intestine, San Jiao
The pattern behind it
The pattern behind it is Heat that has become excess and combined with Dampness, usually in the Liver and Gallbladder. The formula does not merely cool the surface: it removes the Fire, dries and drains the Dampness, and opens a downward route so the pathogenic factor leaves the body rather than being pushed around inside it. The Yin-protecting herbs are there because prolonged Heat damages Blood and fluids, and because the draining herbs would otherwise be too harsh.
Composition
The herbs in Long Dan Xie Gan Tang, with their role and dose.
| Role | Herb | Dose | Properties | Why it is there |
|---|---|---|---|---|
| King | Long Dan Cao | 6 to 9 g | Cold, Bitter | The chief herb: it drains Fire from the Liver and Gallbladder and dries Damp-Heat in those channels. Everything else in the formula adjusts or supports that central action. |
| Deputy | Huang Qin | 6 to 9 g | Cold, Bitter | Adds cooling and drying, particularly for the upper body and the Gallbladder, strengthening the Fire-draining core. |
| Deputy | Zhi Zi | 6 to 9 g | Cold, Bitter | Clears Heat from the Heart and San Jiao and drains it downward, which helps with the restlessness and the dark urine. |
| Assistant | Ze Xie | 9 to 12 g | Cold, Sweet, bland | Drains Dampness through the urine, opening the exit route for the pathogenic factor. |
| Assistant | Mu Tong | 3 to 6 g | Cold, Bitter | Clears Heat from the Heart and Small Intestine and drains it downward through urination. Only the safe species is used; Guan Mu Tong is banned. |
| Assistant | Che Qian Zi | 6 to 9 g | Cold, Sweet | Promotes urination and clears Damp-Heat, reinforcing the downward drainage. |
| Assistant | Sheng Di Huang | 9 to 12 g | Cold, Sweet, bitter | Cools and nourishes the Blood and Yin, so that the Fire does not simply consume what the Liver needs. |
| Assistant | Dang Gui | 3 to 6 g | Warm, Sweet, pungent | Nourishes Blood and keeps it moving. The one warm herb here, it balances the cold mass and protects the Blood. |
| Envoy | Chai Hu | 3 to 6 g | Slightly cool, Pungent, bitter | Enters the Liver and Gallbladder channels and acts as the guide, carrying the rest of the formula into the channels that need it. |
| Envoy | Gan Cao | 3 to 6 g | Neutral, Sweet | Harmonises the formula and protects the Stomach from the bitterness and coldness of the whole. |
Patterns it treats
Liver Fire Blazing
Deep, intense redness of the face with the skin feeling hot to the touch, and colour that concentrates on the upper body. The Fire blazes upward in the Liver channel, which is why the heat shows on the face rather than settling elsewhere.
Liver and Gallbladder Damp-Heat
Redness, itching and weeping in the genital area, with discharge and a surface that feels hot and damp. The Damp-Heat has settled in the Liver channel that encircles the genitals, so the lesions stay wet until the Dampness is drained.
How the formula is built
The structure is a cooling core plus a drainage route plus protection. Long Dan Cao with Huang Qin and Zhi Zi clears the Fire; Ze Xie, Mu Tong and Che Qian Zi make sure the Dampness exits through the urine instead of being left behind; Chai Hu targets the channels; and Sheng Di Huang, Dang Gui and Gan Cao limit the damage that much bitter cold could otherwise do to the Blood and the digestion. Remove the protective herbs and the formula becomes far too harsh for ordinary use; remove the draining herbs and the Dampness stays despite the cooling.
Skin conditions it is used for
Where this formula appears in the skin conditions of the library.
Preparation and use
Traditionally the herbs are cut into small pieces and decocted in water, taken warm. The classical instruction is to take it on an empty stomach, about 30 minutes before food, and to follow it with a light meal to protect the Stomach.
Modifications
- If the Fire is very intense, with high fever, severe headache and markedly red eyes, the cooling herbs are increased.
- If the downward Damp-Heat dominates, with heavy genital discharge or painful urination, the draining herbs are increased.
- If the digestion is delicate, the bitter-cold proportion is reduced and the middle is supported.
- Where jaundice appears, a separate jaundice formula is often combined rather than simply increasing this one.
Timing
Traditionally taken warm on an empty stomach about 30 minutes before food, once or twice daily, with a light meal afterwards to protect the Stomach.
Duration
Short-term use only: usually three to seven days for an acute presentation, and not beyond two weeks without reassessment. It is not a maintenance formula.
Diet while taking it
Avoid the things that generate Heat and Dampness: alcohol, greasy and fried food, and hot spicy food. Reducing sugar and heavy food helps as well.
Safety
Contraindications
Avoid in Spleen and Stomach deficiency with cold signs such as loose stools, poor appetite and fatigue, because the bitter-cold nature can damage already weak digestion. Avoid where headache and red eyes come from Yin deficiency with rising Yang rather than from excess Fire: the formula drains excess and would weaken a deficient person further. Do not use long term.
Interactions
The diuretic herbs can add to pharmaceutical diuretics such as furosemide or hydrochlorothiazide, increasing the risk of dehydration and potassium loss. Caution is also needed with antihypertensive medication, since the formula itself lowers blood pressure.
Pregnancy
Use with caution in pregnancy. Mu Tong has been flagged as potentially harmful in pregnancy, Ze Xie and Che Qian Zi are strongly diuretic and can deplete fluids, and the formula as a whole is intensely bitter and cold. It should not be taken in pregnancy without professional supervision.
Breastfeeding
Caution is advised during breastfeeding, because the strongly bitter-cold nature passes into milk and can affect both mother and infant digestion.
Children
It can be used in children with careful adjustment. Children are described in the tradition as having immature digestion, so the dose is reduced and the coldness is watched closely.
Before you use it
Recorded from the classical record and rewritten in this project's own words. This page is educational: it is not a prescription, and a formula of this strength should only be used under the guidance of a qualified practitioner.
General safety references
General references for herbal hepatotoxicity and herb-drug interactions; they are not specific to this formula.
- Review article: Herbal hepatotoxicity - an update on traditional Chinese medicine preparations. Alimentary Pharmacology & Therapeutics, 2014. PMID: 24844799.
- Interactions between herbal medicines and prescribed drugs: an updated systematic review. Drugs, 2009. PMID: 19719333.
- Warfarin and food, herbal or dietary supplement interactions: a systematic review. British Journal of Clinical Pharmacology, 2021. PMID: 32478963.
Selected PubMed records
Real PubMed records for the modern, non-TCM discussion of this formula. They are references, not a claim that the formula is proven for any skin condition.
- Efficacy and safety of Chinese herbal medicine Long Dan Xie Gan Tang in insomnia: A systematic review and meta-analysis.. Medicine, 2020. PMID: 32176067.
- The efficacy of long-dan-xie-gan-tang in the treatment of herpes zoster: a clinical trial and animal experimental data.. Journal of Tongji Medical University = Tong ji yi ke da xue xue bao, 1986. PMID: 3746978.
Origin and history
Yi Fang Ji Jie (医方集解, Medical Formulas Collected and Analyzed) by Wang Ang, Qing dynasty, 1682 CE. The formula itself is older, attributed to Li Dongyuan (1180-1251).
The formula dates back further than the text usually cited for it. Its original form is attributed to Li Dongyuan, one of the four great masters of the Jin-Yuan period, whose case history involves a patient with the pattern brought on by alcohol. It was later recorded and discussed by Wang Ang in the Yi Fang Ji Jie in 1682, and from there it became one of the standard formulas for Liver and Gallbladder Fire. The name itself summarises the action: long dan (gentian) drains, xie means to drain, and gan is the Liver.
Classical record
此足厥阴、少阳药也。龙胆泻厥阴之热，柴胡平少阳之热，黄芩、栀子清肺与三焦之热以佐之；泽泻泻肾经之湿，木通、车前泻小肠、膀胱之湿以佐之；然皆苦寒下泻之药，故用归、地以养血而补肝，用甘草以缓中而不伤肠胃，为臣使也。
This is a formula for the Foot Jue Yin (Liver) and Shao Yang (Gallbladder) channels. Long Dan Cao drains Heat from Jue Yin, Chai Hu settles Heat in Shao Yang, and Huang Qin and Zhi Zi clear Heat from the Lungs and San Jiao in support. Ze Xie drains Dampness from the Kidney channel, while Mu Tong and Che Qian Zi drain Dampness from the Small Intestine and Bladder. Because these are all bitter, cold, downward-draining herbs, Dang Gui and Sheng Di Huang are used to nourish Blood and supplement the Liver, and Gan Cao to relax the middle so the Stomach and intestines are not harmed.
Yi Fang Ji Jie (医方集解, Variorum of Medical Formulas), Wang Ang, Qing dynasty.
Modern research
Reviewing 14 randomised trials with 1,080 eczema patients, the formula used alone or alongside conventional treatment was reported effective, and laboratory work suggested an effect on T cell proportions. The authors noted the evidence quality was limited.
Evidence note
No controlled trial of this treatment in skin conditions was identified for this entry. What is described here rests on the classical and later materia medica record and on traditional clinical use, not on controlled trial evidence, and it is not a prediction of benefit. Where skin-specific research does exist it is linked above.
Common questions
How is this different from a general cooling formula?
It drains as well as cools. The bitter cold herbs deal with the Fire, but the formula also includes herbs that open a downward route through the urine, so the Dampness leaves the body rather than being suppressed in place.
Why does it contain a warm herb if it is a cold formula?
Dang Gui is warm and nourishes Blood. With so much bitter cold in the formula, some protection for the Blood and the digestion is needed, and it also keeps the Blood moving rather than letting the cold congeal it.
Can it be taken for a long time?
No. It is a short-term draining formula, typically a few days for an acute picture and not beyond about two weeks without reassessment, because prolonged bitter-cold treatment damages digestion and depletes the Yin it is trying to protect.
Why must Guan Mu Tong never be used?
Guan Mu Tong (Aristolochia manshuriensis) contains aristolochic acid, a confirmed human carcinogen that causes irreversible kidney damage. It was removed from the Chinese Pharmacopoeia in 2003 to 2004 and is banned or restricted in several countries. Only the safe species of Mu Tong is used.
Does the research support it?
There are systematic reviews in hypertension, insomnia with Liver Fire features and eczema, and they report benefit, but the included trials are generally small or of limited quality. The evidence supports the traditional use rather than proving it.