Objective:To observe the effects of Wenshen Jianpi Decoction on 5-hydroxytryptamine (5-HT), 5-HT,3, receptor (5-HT,3,R), and 5-HT,4, receptor (5-HT,4,R) in colon mucosa of rats with diarrhea-predominant irritable bowel syndrome (IBS-D). MethodsForty male Sprague-Dawley rats were divided randomly into four groups as the normal group, model group, Chinese medicine group, and western medicine group. Except the normal group,IBS-D model was copied in the other groups by an integrated approach which combined the AL-Chaer ED modeling method,intragastric administration with senna soup,tail tamping stimulation and constraint stress. After successful modeling,the normal and model group were administrated with 0.9% NaCl,the Chinese medicine group was treated with Wenshen Jianpi Decoction,and the western medicine group was treated with pinaverium bromide,with a course of two weeks for intragastric administration. The general situation of rats was observed, the score of abdominal withdrawal reflex(AWR)and the fecal moisture content in rats were measured. The colonic mucosa of rats were collected,the expression of 5-HT was determined by enzymelinked immunosorbent assay and the expression of 5-HT,3,R and 5-HT,4,R were determined by immunohistochemical assay.  Results:Compared with the normal group, the rats in the model group appeared loose stool, dull color of fur and appetite loss, meanwhile the AWR scores of rats and fecal moisture content increased,the levels of 5-HT and the optical density of 5-HT3R and 5-HT4R in the colonic mucosa increased, with statistically significant differences (P,<,0.05, P,<,0.01). Compared with the model group,the AWR scores,fecal moisture content and expression of 5-HT,5-HT3R,5-HT4R in the colonic mucosa of the Chinese medicine group decreased,with statistically significant differences (P,<,0.05, P,<,0.01).  Conclusion:The comprehensive effects of Wenshen Jianpi Decoction in the treatment of model rats with IBS-D may involve with the regulating 5-HT and its receptors,regulating enteric nervous system,reducing bowel movement and secretion, and decreasing intestinal visceral hypersensitivity.