What Xiao Feng San is for
The skin is itchy, red and weeping. The itch moves from one place to another, the lesions ooze a clear fluid or crust over, and warmth makes both worse. Scratch marks and crusts sit beside fresh red patches. The explanation is three factors at once: Wind makes the itch move, Heat reddens it and Dampness makes it weep, on a base of Blood that is not quite sufficient. The formula takes all four at once.
The redness is bright and the surface is wet rather than dry, and the itch is worse in warmth and under strain. Hives that come and go, a contact reaction, a mild drug rash and the early weeping stage of eczema all share this picture. What separates the picture from ordinary dryness is the oozing: Dampness is present, so the tissue is damp and heavy rather than thin and rough, and the lesions leave crusts where the fluid has dried.
Four jobs run in parallel. Jing Jie, Fang Feng, Niu Bang Zi and Chan Tui disperse the Wind that drives the movement, and Chan Tui also eases the itch directly. Shi Gao, Zhi Mu and Ku Shen clear the Heat that reddens the skin, with Zhi Mu moistening so the cooling does not leave it parched. Cang Zhu and Mu Tong drain the Dampness that makes it weep. Dang Gui, Sheng Di Huang and Hei Zhi Ma nourish the Blood and moisten, which is what lets the formula run for weeks without leaving the skin rough.
Pale, cold skin without heat signs is the wrong picture, and the cooling and drying herbs would leave it worse. Where the digestion is weak, the bitter cold herbs need care. Because the formula contains Blood-moving and dispersing herbs, it is used with caution in pregnancy, and it is given for a limited course and then reassessed rather than continued indefinitely. A rash from a new medicine needs medical advice before anything else.
Actions
- Dispels Wind and stops itching
- Clears Heat
- Drains Dampness
- Nourishes Blood
- Cools the Blood
Properties
- Taste and temperature: Predominantly pungent and bitter with a sweet undertone. Pungent herbs disperse Wind and open the pores, bitter herbs dry Dampness and clear Heat, and the sweet herbs nourish Blood and harmonise.
- Organs: Lungs, Spleen, Liver, Stomach
- Channels: Lung, Spleen, Liver
The pattern behind it
The pattern is Wind, Heat and Dampness acting together on a base of Blood that is not quite sufficient. Wind explains the itch that moves and comes and goes; Heat explains the redness and the worsening with warmth; Dampness explains the oozing and crusting. Nourishing the Blood is included because repeated itching and drying treatment both consume it, and because the skin needs substance to recover.
Composition
The herbs in Xiao Feng San, with their role and dose.
| Role | Herb | Dose | Properties | Why it is there |
|---|---|---|---|---|
| Jing Jie | 6 to 10 g | Slightly warm, Pungent | Disperses Wind and releases the surface, addressing the itch that moves. | |
| Fang Feng | 6 to 10 g | Slightly warm, Pungent, sweet | The standard Wind herb, used to settle the itch and the weather sensitivity. | |
| Niu Bang Zi | 6 to 10 g | Cold, Pungent, bitter | Disperses Wind-Heat and vents rashes, useful where the eruption is spreading. | |
| King | Chan Tui | 6 to 10 g | Cold, Sweet, salty | Disperses Wind and clears Heat while easing itching, a leading herb for itchy eruptions. |
| Cang Zhu | 6 to 10 g | Warm, Pungent, bitter | Dries Dampness strongly, addressing the oozing and the heavy feeling. | |
| Ku Shen | 6 to 10 g | Cold, Bitter | Clears Heat and dries Dampness and is used for itchy, weeping skin; also applied topically. | |
| Mu Tong | 3 to 6 g | Cold, Bitter | Drains Dampness and clears Heat through the urine. Only the safe species is used; Guan Mu Tong is banned. | |
| Shi Gao | 6 to 10 g | Cold, Sweet, pungent | Clears strong Heat while protecting fluids, which is why it can be used without over-drying. | |
| Zhi Mu | 6 to 10 g | Cold, Bitter, sweet | Clears Heat and moistens, balancing the drying herbs. | |
| Dang Gui | 6 to 10 g | Warm, Sweet, pungent | Nourishes Blood so the drying and dispersing do not leave the skin rough. | |
| Sheng Di Huang | 6 to 10 g | Cold, Sweet, bitter | Cools the Blood and nourishes Yin, supporting the skin's recovery. | |
| Envoy | Hei Zhi Ma | 6 to 10 g | Neutral, Sweet | Nourishes Blood and moistens the skin, and is the herb that makes the formula suitable for longer use. |
| Gan Cao | 3 to 6 g | Neutral, Sweet | Harmonises the formula and supports the middle. |
Patterns it treats
Wind-Heat
Itchy red skin that weeps or crusts, with the itch moving from place to place and worsening with warmth. Wind drives the movement, Heat reddens the surface and Dampness makes it weep, on a base of Blood that is not quite sufficient.
How the formula is built
The formula runs four jobs in parallel. Wind is dispersed by Jing Jie, Fang Feng, Niu Bang Zi and Chan Tui; Heat is cleared by Shi Gao, Zhi Mu and Ku Shen; Dampness is drained by Cang Zhu and Mu Tong; and Blood is nourished by Dang Gui, Sheng Di Huang and Hei Zhi Ma. That last group is the difference between this and a simple cooling powder: it prevents the treatment from leaving the skin dry and itchy in a different way.
Skin conditions it is used for
Where this formula appears in the skin conditions of the library.
Preparation and use
Traditionally taken as a powder, or decocted in water and taken warm in two divided doses.
Modifications
- If the Heat is marked, the cooling herbs are increased.
- If oozing dominates, the Dampness-draining herbs are increased.
- If the itch is severe and generalised, the Wind-dispersing group is strengthened.
- If the skin has become dry and thickened from chronic scratching, the Blood-nourishing herbs are increased.
Timing
Traditionally taken as a powder or warm decoction, in two divided doses.
Duration
For an acute flare, one to two weeks. For subacute or recurring conditions, four to eight weeks with regular reassessment.
Diet while taking it
Avoid alcohol, fried food and hot spicy food while the skin is red and itchy; these are the dietary sources of the Heat and Dampness.
Safety
Contraindications
Avoid in skin conditions from Cold deficiency or Yang deficiency: pale, cold skin without heat signs would be worsened by the cooling and Heat-clearing herbs. Also use care where the digestion is weak, because several herbs are bitter and cold.
Interactions
Gan Cao may interact with antihypertensives and diuretics because glycyrrhizin can cause potassium loss and raise blood pressure. The formula may also add to the effect of blood-sugar-lowering medication.
Pregnancy
Use with caution in pregnancy. Mu Tong is classically treated cautiously in pregnancy, Niu Bang Zi raises separate concerns because of its dispersing action, and the formula contains several cooling herbs.
Breastfeeding
Use only under professional guidance.
Children
Used in children with reduced dose and professional supervision.
Before you use it
Recorded from the classical record and rewritten in this project's own words. Educational only: not a prescription.
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.
- Traditional Chinese medicine for food allergy and eczema.. Annals of allergy, asthma & immunology : official publication of the American College of Allergy, Asthma, & Immunology, 2021. PMID: 33310179.
- Efficacy of herbal medicine Xiao-Feng-San combined with auricular acupuncture for atopic dermatitis: A randomized controlled trial.. Integrative medicine research, 2026. PMID: 41104111.
Origin and history
Wai Ke Zheng Zong (外科正宗, Orthodox Manual of External Medicine) by Chen Shigong, Ming dynasty, 1617 CE.
Chen Shigong published the formula in the Wai Ke Zheng Zong in 1617, a Ming dynasty manual of external medicine that remains one of the standard sources for skin formulas. Its classical indication is precisely what the page still describes: Wind-Dampness soaking into the Blood vessels to produce unceasing itch, and Wind-Heat urticaria with spots and patches over the body.
Classical record
治风湿浸淫血脉，致生疥疮，瘙痒不绝，及大人小儿风热瘾疹，遍身云片斑点。
It treats Wind-Dampness soaking into the Blood vessels, giving rise to scabies-like sores with unceasing itching, and Wind-Heat urticaria in adults and children with patches and spots over the whole body.
Wai Ke Zheng Zong (外科正宗, Orthodox Manual of External Medicine), Volume 4, Chen Shigong, Ming dynasty, 1617.
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
Why does an itchy skin formula contain Blood tonics?
Because repeated itching and drying treatment both consume the Blood that keeps skin supple. Without them the formula would clear the rash and leave the skin dry and rough.
How do I choose between this and Dang Gui Yin Zi?
Look at the skin and tongue. Red, damp and moving with a red tongue and yellow coat points to Xiao Feng San; pale, dry and depleted with a pale tongue points to Dang Gui Yin Zi.
Can it be used for a drug rash?
Only with medical advice. A drug reaction can be serious, and any rash with fever, blistering, mouth involvement or spreading needs urgent assessment.
How long can it be taken?
One to two weeks for an acute flare, and four to eight weeks for recurring conditions with regular reassessment.