San Huang Tang — Three Yellows Decoction
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What is San Huang Tang?
San Huang Tang (“Three Yellows Decoction”, 三黄汤) is a classical Chinese formula combining the three principal bitter-cold antimicrobial “yellow” herbs of the Chinese materia medica: Huang Lian (Coptis chinensis), Huang Qin (Scutellaria baicalensis) and Huang Bai (Phellodendron amurense). The three herbs share a striking yellow colour from their content of berberine and related isoquinoline alkaloids, and together produce one of the most powerful Damp-Heat-clearing and Heat-toxin-resolving combinations in the Chinese materia medica.
The formula has been used in various compositions across centuries of Chinese medical literature; the related San Huang Xie Xin Tang (Three Yellows Drain the Heart Decoction) from Zhang Zhongjing’s Jin Gui Yao Lue uses Da Huang in place of Huang Bai for stronger purgative action in upper-body Heat. The Huang Lian + Huang Qin + Huang Bai combination described here is the form most commonly used in modern integrative practice for Damp-Heat patterns in the lower jiao and as a broad antimicrobial.
San Huang Tang TCM pattern
Prescribed for Damp-Heat and Heat-toxin patterns in the three jiao, with each Huang herb addressing a different anatomical level: Huang Lian for the Heart and Stomach (upper-middle jiao), Huang Qin for the Lung and upper jiao, Huang Bai for the lower jiao (intestines, bladder, lower limbs). Together they cover the body from chest to pelvis. Key features include: bitter taste in the mouth, foul-smelling stool or urine, burning sensations in the digestive or urinary tract, yellow greasy tongue coating, rapid wiry or slippery pulse, and the inflammatory features of an underlying Damp-Heat pattern. The pattern is most often seen in modern practice in chronic gut conditions, recurrent urinary infections, certain skin conditions with Heat-toxin features, and the Damp-Heat subset of SIBO and IBS-D.
Key herbs
- Huang Lian (Coptis chinensis rhizome, 2-9g) — the chief herb; bitter, cold; rich in berberine; clears Heat and resolves Heat-toxin, particularly from the Heart and Stomach; broad-spectrum antimicrobial including against Helicobacter pylori, Giardia, and dysbiotic gut bacteria
- Huang Qin (Scutellaria baicalensis root, 3-10g) — deputy; bitter, cold; clears Heat from the upper jiao; antimicrobial and anti-inflammatory through baicalin and baicalein; particularly useful where there is Lung and respiratory involvement
- Huang Bai (Phellodendron amurense bark, 3-12g) — deputy; bitter, cold; clears Heat from the lower jiao; particularly useful for genitourinary, intestinal and lower-limb Damp-Heat patterns; also rich in berberine
Formula actions
- Clears Heat throughout the three jiao
- Drains Damp-Heat
- Resolves Heat-toxin
- Broad antimicrobial action against bacteria, protozoa and fungal overgrowth
Conditions treated
- SIBO with Damp-Heat features — hydrogen-dominant SIBO with urgent, burning loose stools, foul wind and a sensation of heat in the lower abdomen
- IBS-D with Damp-Heat presentation
- Intestinal parasites and protozoan infections, particularly Giardia, where the Huang Lian berberine action is most relevant
- Acute gastroenteritis and dysentery patterns with Damp-Heat
- Recurrent urinary tract infections with burning and frequency (lower-jiao Damp-Heat, particularly responsive to Huang Bai)
- Acne, rosacea and other inflammatory skin conditions with Heat-toxin features
- Eczema with Damp-Heat presentation (red, hot, weeping, infected)
- Adjunct in the SIBO/parasite clearance phase as part of an integrative protocol
Modern research
Each of the three Huang herbs has been extensively studied. Huang Lian and Huang Bai both contain high concentrations of berberine, one of the most extensively researched plant alkaloids in pharmacology, with documented antimicrobial, anti-inflammatory, glucose-lowering, lipid-lowering and gut-microbiome-modulating effects. Huang Qin contains baicalin and baicalein with anti-inflammatory, antiviral and neuroprotective effects. The combination of all three has been particularly studied in the context of the herbal SIBO protocols popularised by the 2014 Chedid study at Johns Hopkins, where berberine was a principal active component of the herbal antimicrobial arm shown to be equivalent to rifaximin for SIBO clearance.
Cautions
San Huang Tang is a strongly bitter and cooling formula. It is not appropriate for Spleen Yang deficiency, Cold patterns or constitutionally cold patients; long-term use damages the Spleen and should be avoided. The formula is typically prescribed for short courses (2–6 weeks during an active clearance phase) and followed by Spleen-tonifying formulae such as Liu Jun Zi Tang or Si Jun Zi Tang to consolidate. Avoid in pregnancy. Berberine-containing formulae interact with several medications — particularly metformin (additive glucose-lowering), antihypertensives, anticoagulants and cyclosporine — and should be coordinated with the patient’s prescriber. Always consult a qualified Chinese herbalist registered with the Register of Chinese Herbal Medicine (RCHM). Online herbal consultations are available. See the prices page for costs.
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