Objective:To evaluate the effect of Shugan Jianpi Granule (舒肝健脾颗粒,SJG) on the number of gut mucosal serotonin-positive cells (5-HT+C) in patients with irritable bowel syndrome (IBS) of stagnated Gan-qi attacking Pi (SGAP) syndrome type.Methods:Twenty-four patients were randomized equally into three groups.All were treated with the basic conventional treatment by cognition-behavior therapy with assistance of lactein 3 tablets thrice a day.Additionally,24 g of SJG was given three times a day to group A,and the same dosage of SJG and Smecta 15 g thrice a day was given to group B,while no additional treatment was given to the control group.The number of 5-HT+C was measured respectively before and two weeks after treatment by immunohistochemical method.Results:The number of 5-HT+C decreased after treatment in all the three groups (P＜0.05),but the decrement was more significant in the two test groups than in the control group (P＜0.05 and P＜0.01,respectively),while comparison of 5-HI+C between the two test groups showed insignificant difference (P＞0.05).Conclusion:SJG can reduce the number of 5-HT+C in IBS patients of SGAP syndrome type,and its effect is enhanced when used in combination with Smecta.