Objective To observe the clinical effect of Huangxin Runchang Pian in the treatment of slow transit constipation. Methods Ninety patients with mild or moderate slow transit constipation were randomized into a treatment group（ 45 cases） and a control group（ 45 cases）. The treatment group was given Huangxin Runchang Pian; the control group was given Danggui Longhui Wan（ 当归龙荟丸）. Both groups were given 6 g of the corresponding herbal medicine each time

twice every day

for 3 weeks. Patients’ sense of anal obstruction during defecation

sense of incomplete defecation

defecation difficulty level

stool frequency

each defecation time

sense of abdominal distension

and stool property symptom score in both groups were examined before and after treatment

as well as one month after stopping medication. The clinical effect was evaluated. Results The total clinical effective rate after treatment and 1 month after stopping medication was 95. 6% and 82. 2% in the treatment group

and93. 3% and 80. 0% in the control group

respectively. There was no significant difference between two groups（ P >0. 05）. Patients’ symptom scores in both groups decreased after treatment and 1 month after stopping medication（ P < 0. 01）. The scores of defecation difficulty level and each defecation time in the treatment group after treatment and 1 month after stopping medication were lower than those in the control group at the same time points（ P < 0. 05）.Conclusion Huangxin Runchang Pian seems to be effective in treating mild or moderate slow transit constipation

especially in improving defecation difficulty level and shorting defecation time.