What Di Dang Tang is for
This formula is for stasis that has set hard in the tissue. On the skin it reads as colour that will not shift: dusky purple-brown patches that feel firm or thickened under the finger. It is the hardness rather than the colour alone that says how old the stagnation is, and why it has outlasted the moving herbs that would clear a fresher bruise.
The skin shows fixed, dusky discolouration, more brown-purple than red, and the area feels indurated, as though the tissue beneath has become denser than the skin beside it. Pressure does not blanch it and the colour returns unchanged. The surface itself is usually intact, which is what makes the picture easy to mistake for ordinary pigmentation; the difference is the firmness, and the fact that nothing has shifted it.
Shui Zhi and Meng Chong are Blood-breaking insects, and in this tradition that is what old, hardened stasis is said to need: something that reaches tissue the ordinary moving herbs pass over. Tao Ren moves the Blood that is still liquid, and Da Huang purges and drives the congested Blood downward. Nothing in the formula is nourishing or moderating, so the change in the skin is a slow softening and a return of colour rather than any surface effect.
The strength is the point and the danger. This is a short, supervised course for a robust adult, never a long-term remedy, and it is absolutely contraindicated in pregnancy and in anyone depleted. Any new firm mass, or pigmentation that is changing, needs medical assessment before it is read as stasis, because the formula acts on the pattern and cannot tell one cause from another.
Actions
- Breaks deep fixed Blood stasis
- Dispels hard masses
- Moves Blood downward
- Relieves severe fixed pain
Properties
- Taste and temperature: Predominantly bitter and salty with a cold quality. Bitter and cold break stasis and purge, salty softens and penetrates.
- Organs: Liver, Heart, Large Intestine
- Channels: Liver, Heart, Large Intestine
The pattern behind it
The pattern is deep fixed Blood stasis that has congealed into a mass or a fixed area of discolouration. The stasis is old and hard, which is why gentler moving herbs have not reached it. The formula uses insects and a purgative to break through it.
Composition
The herbs in Di Dang Tang, with their role and dose.
| Role | Herb | Dose | Properties | Why it is there |
|---|---|---|---|---|
| Deputy | Shui Zhi | 3 to 6 g | Neutral, Salty, bitter | A leech that breaks old fixed stasis and moves Blood. |
| King | Meng Chong | 3 to 6 g | Cool, Bitter | The leading Blood-breaking insect, reaching stasis other herbs cannot. |
| Tao Ren | 9 to 12 g | Neutral, Bitter, sweet | Moves Blood, supporting the breaking action. | |
| Da Huang | 9 to 12 g | Cold, Bitter | Purges and moves Blood downward, clearing the congested stasis. |
Patterns it treats
Blood Stagnation
Dusky purple-brown patches that feel firm and do not blanch under pressure, with colour that has not shifted despite gentler treatment. The stagnation has set in the tissue rather than the surface, which is why the texture changes before the colour does.
How the formula is built
Two insects to break the stasis and two herbs to move and purge it. Nothing nourishing or moderating is included, which is why the formula is short, strong and only for robust patients.
Skin conditions it is used for
Where this formula appears in the skin conditions of the library.
Preparation and use
Decocted and taken briefly, under close professional supervision.
Modifications
- The classical text uses it in a short course and stops when the stasis moves.
- If the person is depleted, it is not used.
- If the mass persists, a different approach is needed.
- In pregnancy it is absolutely contraindicated.
Timing
Given briefly under close supervision, stopped when the stasis moves.
Duration
Short course only, a few days, with reassessment.
Diet while taking it
Avoid cold raw food and alcohol.
Safety
Contraindications
Absolutely contraindicated in pregnancy. Avoid in depleted patients, in active bleeding, and in anyone without deep fixed stasis. Any new mass needs medical assessment first.
Interactions
The Blood-breaking herbs may add to anticoagulants, and Da Huang can affect electrolytes. This formula requires a practitioner.
Pregnancy
Absolutely contraindicated. The Blood-breaking insects and the purgative can cause miscarriage.
Breastfeeding
Contraindicated without specialist guidance.
Children
Used only with extreme caution under specialist supervision.
Before you use it
Recorded from the classical record and rewritten in this project's own words. Educational only: not a prescription. The insects and purgative make this professional-only, and any new mass 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.
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.
- Di-Dang-Tang suppresses ferroptosis in the hippocampal CA1 region by targeting PGK1/NRF2/GPX4 signaling pathway to exert neuroprotection in vascular dementia.. International immunopharmacology, 2025. PMID: 39946772.
- Investigating metabolic characteristics of type 2 diabetes mellitus-related cognitive dysfunction and correlating therapeutic effects of Di Dang Tang in animal models.. Journal of ethnopharmacology, 2025. PMID: 39826792.
Origin and history
Shang Han Lun (伤寒论, Treatise on Cold Damage) by Zhang Zhongjing, Eastern Han dynasty, around 220 CE.
Di Dang Tang is one of the sharpest formulas in the classical literature, recorded by Zhang Zhongjing for stasis that has become hard and fixed. Its brevity and strength are deliberate, and it has always been reserved for short supervised courses.
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
What is it used for?
Deep fixed Blood stasis with a hard mass or dusky fixed discolouration, in a robust patient, for a short supervised course.
Why does it contain insects?
The classical view is that only Blood-breaking insects can reach stasis that has become hard and fixed.
Is it safe without supervision?
No. It is strong and includes a purgative, and it is absolutely contraindicated in pregnancy.
Can it treat spider veins?
No, not as a primary treatment. Visible veins need medical assessment, and this formula is not for cosmetic vascular changes.