Objective: To study the effect of Dachengqi decoction on defecating function in the treatment of constipation. Method: In normal mice

the water deprivation constipation model and compound diphenoxylate(DC)induced constipation model were established.Mice were randomly divided into control group

model control group

positive control group of Maren capsule (2 g·kg-1) and three dosage groups of Dachengqi decoction (29.6

14.8

7.4 g·kg-1)

each group was respectively treated with corresponding drugs

and then the time of defecation of the first black feces

the number of feces within 6 hours

and the promoting rate of ink were measured. Result: In the mice treated by Dachengqi decoction

the time course of excretion of carbon powder was shortened and the counts of black feces were significantly increased (P<0.01).The acceleration of the propulsive rates were increased in the normal mice and compound diphenoxylate (DC) model mice which were treated with Dachengqi decoction (P<0.01). Conclusion: Dachengqi decoction has a strong promoting defecation and increasing intestinal peristalsis in normal and constipation model mice

it would provide experimental basis for clinical application.