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Dachengqi Tang


Potent Purgative Decoction

  1. 大承气汤
  2. 大承氣湯

The Prescription of Dachengqi Tang


The book Shang Han Lun


  • Da Huang (Radix et Rhizoma Rhei) 12 g,
  • Hou Po (Cortex Magnoliae Officinalis) 15 g,
  • Zhi Shi (Fructus Aurantii Immaturus) 15 g,
  • Mang Xiao (Natrii Sulfas) 9 g.


Da Huang: The principal drug, being bitter in flavor and cold in nature, purging heat to relax the bowels, removing stagnancy in the stomach and intestines.

Mang Xiao: Being salty in flavor and cold in nature, purging heat, softening hard masses, moistening dryness.

Hou Po and Zhi Shi: Promoting the circulation of Qi to resolve masses, relieving fullness and distention, assisting Mang Xiao and Da Huang in eliminating stagnancy to remove accumulation of heat.

The Effect of Dachengqi Tang


Drastically eliminating heat accumulation and relieving constipation.


Excess syndrome due to interior heat, marked by constipation, frequent farting, fullness and distention in the gastric and abdominal region, tenderness with hard sensation in the abdomen, or even tidal fever, delirium, persistent sweating in the soles and palms, dry and yellowish tongue coating with prickles or dry black fissure tongue coating, and deep forceful pulse, or marked by green watery stools, pain in the abdomen or around the umbilicus, palpable masses in the abdomen, dry mouth and tongue, and slippery forceful pulse; including such diseases with the above symptoms as acute simple intestinal obstruction, cohesive intestinal obstruction, ascaris intestinal obstruction, acute cholecystitis, acute appendicitis, acute bacillary dysentery, toxic dysentery, schizophrenia, etc.


Decocted in water for oral dose to be taken twice, Da Huang and Mang Xiao should be decocted for a shorter time in order to keep their purgative action.


Because of its drastic action, this prescription should not be prescribed for pregnant women. The administration of it should be stopped once its effectiveness appears.