Da Cheng Qi Tang

大承气汤 (Da Cheng Qi Tang)

Source: Shang Han Lun — Zhang Zhongjing (Han, 220)

Yang Ming organ pattern excess heatSevere constipation with hard stoolAbdominal fullness and distensionHigh fever with constipationIntestinal obstructionHeat delirium from bowel obstructionAcute appendicitis (adjunctive)

Description

Da Cheng Qi Tang (Major Order the Qi Decoction) is the most powerful purgative formula in TCM, clearing Yang Ming organ excess heat through strong purgation. It treats dry stool, severe constipation, and accumulation of heat in the Large Intestine with signs of Yang Ming heat excess. Given its strength, it should be used only when the condition clearly matches and discontinued once the bowels move.

Composition

Herb	Amount	%	Role	Function
Mang Xiao	9g	18.75%	Chen (Deputy)	Softens hardness, moistens dryness, purges heat.
Hou Po	15g	31.25%	Zuo (Assistant)	Moves Qi, disperses fullness, eliminates distension.
Zhi Shi	12g	25%	Zuo (Assistant)	Breaks Qi stagnation, reduces accumulation.
Da Huang	12g	25%	Jun (Chief)	Purges heat and stagnation, clears Large Intestine.

Total weight: 45g

Preparation

Decoct Da Huang separately for only 3–5 minutes (over-cooking reduces purgative effect). Add Mang Xiao to the strained decoction just before taking. Take on empty stomach.

Dosage

Decoction: Take warm. Discontinue immediately once stools loosen. Not for use in deficiency patients, post-partum, or during pregnancy.