What Gan Lu Xiao Du Dan is for
This is the formula for skin that erupts in the middle of an acute Damp-Heat illness. The lesions are boils, hot inflamed follicles and greasy papules, sitting on skin that looks oily, congested and cross rather than dry. The turbidity that coats the tongue is the same turbidity that makes the skin look unclean, and toxicity is what drives the boil itself. It is a short course for the acute episode.
The skin in this pattern is hot, greasy and angry. Boils and inflamed follicles appear in crops, often where clothing or sweat collects, each one with a red rim and a yellow centre, and the surrounding skin looks oily rather than dry. Between the lesions there are small red papules and a general congestion of the surface. The greasy yellow coating on the tongue is the visible sign of the turbidity, and the same turbidity shows on the skin as an oiliness and a dull look that washing does not change. The boils themselves are read as toxicity.
The formula works on that picture from several directions at once, which is why it suits a skin episode that is hot and greasy rather than simply red. Hua Shi and Yin Chen drain the Dampness, and Yin Chen is the herb used where hot dampness reaches the skin. Huang Qin, Lian Qiao and She Gan clear the Heat and resolve the toxicity that forms the boil. Shi Chang Pu, Huo Xiang and Bai Dou Kou are aromatic, lifting the turbid quality that makes the surface look dull and oily. Bo He opens the skin so the Heat vents rather than sitting in the follicle.
What makes this a skin formula rather than a general one is the direction of the clearing. The herbs give the Dampness a route out, dry the turbidity from the middle and open the surface, so the eruption can resolve instead of spreading deeper. It is used for the acute crop of boils or follicle inflammation that arrives with the hot damp episode, and it is stopped when that episode settles. It is wrong for cold damp skin, for dry chronic eczema, and for any picture in which the skin is pale and cool rather than hot and greasy.
Actions
- Clears Heat and resolves toxicity
- Transforms Dampness and turbidity
- Opens the orifices and clears the head
- Drains Damp-Heat through the urine
Properties
- Taste and temperature: Predominantly bitter and aromatic with a sweet note. Bitter clears Heat and dries, aromatic transforms turbidity and opens, sweet protects the Stomach.
- Organs: Spleen, Stomach, Lungs, Large Intestine
- Channels: Spleen, Stomach, Lung
The pattern behind it
The pattern is Damp-Heat with toxicity affecting the whole body. Dampness produces the heaviness, the greasy coat and the turbidity; Heat produces the thirst, the bitter taste and the rapid pulse; toxicity produces the eruptions. The formula drains, clears, transforms and opens at the same time, which is why it is used for the broad picture rather than a single symptom.
Composition
The herbs in Gan Lu Xiao Du Dan, with their role and dose.
| Role | Herb | Dose | Properties | Why it is there |
|---|---|---|---|---|
| Hua Shi | 15 to 18 g | Cold, Sweet, bland | Guides Damp-Heat out through the urine, the main draining route. | |
| Yin Chen | 10 to 15 g | Slightly cold, Bitter, pungent | Clears Damp-Heat and is used for hot damp conditions affecting the skin and the body. | |
| King | Huang Qin | 6 to 10 g | Cold, Bitter | Clears Heat from the upper and middle body, addressing the Heat component strongly. |
| Shi Chang Pu | 5 to 10 g | Warm, Pungent | Transforms turbidity and opens the orifices, clearing the heavy head. | |
| Huo Xiang | 3 to 6 g | Slightly warm, Pungent | An aromatic herb that transforms Dampness and releases the middle. | |
| Bai Dou Kou | 2 to 5 g | Warm, Pungent | Warms and dries the middle, moving the Dampness with aromatic pungency. | |
| King | Mu Tong | 3 to 6 g | Cold, Bitter | Drains Damp-Heat through the urine. Only the safe species is used; Guan Mu Tong is banned. |
| Lian Qiao | 5 to 10 g | Slightly cold, Bitter | Clears Heat and resolves toxicity. | |
| She Gan | 3 to 6 g | Cold, Bitter, pungent | Clears Heat and resolves toxicity, particularly for the throat and upper body. | |
| Chuan Bei Mu | 3 to 6 g | Slightly cold, Bitter, sweet | Transforms Phlegm and disperses nodules, addressing the turbidity that has thickened. | |
| Bo He | 3 to 6 g | Cool, Pungent | Disperses and clears the surface, helping the Heat vent outward. |
Patterns it treats
Damp-Heat invading the Spleen
Skin that erupts in crops of greasy boils and hot inflamed follicles, with an oily, congested look that washing does not shift. The turbidity of Damp-Heat shows as that oiliness and the toxicity as the boil. This formula drains and clears the pair rather than drying the surface.
How the formula is built
The formula works in layers: draining herbs give the Dampness a route out, cooling herbs clear the Heat, aromatic herbs transform the turbidity and open the head, and toxicity-resolving herbs address the eruptions. That breadth is why it is used for the general Damp-Heat picture rather than for a single location.
Skin conditions it is used for
Where this formula appears in the skin conditions of the library.
Preparation and use
Taken as a powder or prepared pills, or decocted, in two divided doses.
Modifications
- If the Heat is marked, cooling herbs are increased.
- If the Dampness dominates, draining and aromatic herbs are increased.
- If the throat is sore, it is cleared directly.
- If the pattern becomes cold, the formula is stopped and warming used.
Timing
Taken in two divided doses.
Duration
Acute use: five to fourteen days, reassessed frequently as symptoms evolve.
Diet while taking it
Light diet; avoid alcohol, greasy and sweet food, and cold raw food.
Safety
Contraindications
Avoid in Yin deficiency with internal Heat, where the draining and aromatic herbs would dry the body further. Avoid in cold-damp patterns with a white wet coat.
Interactions
The draining herbs can add to diuretics. Mu Tong must come from the approved species, because Guan Mu Tong is banned for kidney toxicity.
Pregnancy
Use with caution in pregnancy. Mu Tong promotes urination and is classically treated with care in pregnancy, and the aromatic draining herbs need guidance.
Breastfeeding
Use only under professional guidance.
Children
Used only with professional supervision and reduced dose.
Before you use it
Recorded from the classical record and rewritten in this project's own words. Educational only: not a prescription, and a febrile illness with jaundice or a spreading eruption needs medical assessment.
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.
Origin and history
Yi Xiao Mi Chuan (医效秘传, Secret Transmission of Medical Efficacy), attributed to Ye Tianshi, Qing dynasty, 18th century.
Gan Lu Xiao Du Dan comes from the Qing warm-disease tradition, where Damp-Heat was recognised as a distinct pattern requiring aromatic transformation as well as draining. Its name, sweet dew resolving toxicity, refers to the cooling and clearing effect, and it remains one of the standard formulas for summer heat with turbidity.
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
Is this a summer formula?
It is often used in hot humid weather and for Damp-Heat illnesses, but it can be used whenever the pattern matches: heavy head, bitter taste, greasy yellow coat.
Why are there aromatic herbs in a cooling formula?
Because Dampness is heavy and turbid, and aromatics transform it and open the head in a way that cooling alone cannot.
Can it help skin eruptions?
Yes, where the eruption is part of a broader Damp-Heat picture. It is not a treatment for chronic dry skin.
How long is it taken?
Five to fourteen days, reassessed as the illness evolves.