Bai Tou Weng Tang — Pulsatilla Decoction

On this page

1. Overview
2. TCM pattern
3. Key herbs
4. Formula actions
5. Conditions treated
6. Cautions

What is Bai Tou Weng Tang?

Bai Tou Weng Tang — Pulsatilla Decoction — is a classical Shang Han Lun formula for damp-heat dysentery. It is one of the most important formulas in Chinese herbal medicine for the kind of bloody, mucoid, foul-smelling diarrhoea seen in acute bacterial dysentery, amoebic colitis and ulcerative colitis flares with heat features.

I prescribe Bai Tou Weng Tang as part of bespoke herbal formulas from pharmaceutical-grade granules sourced from Sun Ten in Taiwan.

Bai Tou Weng Tang TCM pattern

Prescribed for Damp-Heat lodged in the Large Intestine: acute bloody dysentery with mucus and pus, intense abdominal pain, severe tenesmus, burning sensation in the anus, fever, thirst, scanty dark urine, a yellow greasy tongue coat and a slippery rapid pulse.

Key herbs

1. Bai Tou Weng — chief herb; clears heat-toxin from the Blood and cools the Intestines
2. Huang Lian — clears Damp-Heat from the middle and lower Burner
3. Huang Bai — clears Damp-Heat from the lower Burner
4. Qin Pi (Fraxinus bark) — clears heat, dries Damp and astringes the Intestines

Formula actions

1. Clears heat-toxin and cools the Blood
2. Dries Damp in the Large Intestine
3. Resolves dysentery with bleeding

Conditions treated

1. Acute bacterial dysentery (alongside conventional antibiotics where appropriate)
2. Amoebic dysentery with bloody mucoid stools
3. Ulcerative colitis flares with bleeding, urgency and damp-heat features
4. Acute infective gastroenteritis with damp-heat presentation
5. Selected presentations of haemorrhoidal bleeding from damp-heat in the lower Burner

Cautions

Contraindicated in cold-deficient diarrhoea and chronic non-inflammatory loose stools. Acute dysentery and bloody diarrhoea require prompt medical assessment; herbal therapy is adjunctive in serious presentations. Avoid in pregnancy except under specialist supervision.

Always consult a qualified Chinese herbalist registered with the Register of Chinese Herbal Medicine (RCHM). Online herbal consultations are available.

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