Objective To evaluate the effect of Liqi Tongbian Formula（理气通便方） in the treatment of slow transit constipation with qi stagnation pattern（STC-QS）. Methods Sixty STC-QS patients were randomly divided into treatment group and control group

with 30 patients in each group. Four-week oral administration of Liqi Tongbian Formula（one dose daily） or mosapride citrate tablets plus wheat cellulose granules were given in treatment group or control group

respectively. Symptoms score of qi-stagnation constipation

severity score of chronic constipation

the number of spontaneous complete bowel movements per week

and the 72 h colon discharge rate were assessed before and after treatment. Results Compared to control group

treatment group had significantly lower symptom scores regarding stool traits

laborious defecation

defecation time

feeling of incomplete defecation

defecation frequency

abdominal distension

borborygmus

flatus

belching

moodiness

fullness and discomfort in the chest and rib-side after treatment（P<0.05）. The number of completely spontaneous defecation per week and 72 h colon discharge rate in both treatment and control group increased after treatment

and more improvements were seen in treatment group than control group（P<0.05 or P<0.01）. The severity score of chronic constipation in the treatment group significantly decreased after treatment（P<0.05）

while the change in control group was not significantly different（P>0.05）

suggesting a favorable improvement in treatment group than control group（P<0.05）. Conclusion Liqi Tongbian Formula can improve the clinical symptoms in patients with STC-QS

as well as promote spontaneous defecation

and restore colonic transit function.