Objective: To explore clinical efficacy of Tongxie Anpi decoction combined with trimebutine maleate tablets for treating diarrhea-predominant irritable bowel syndrome (IBS-D) with hepatic stagnation and splenic deficiency as well as its effect on 5-hydroxytryptamine (5-HT) and calcitonin gene related peptide (CGRP). Method: The 80 patients were randomly divided into treatment group and control group (n=40 in each group). Patients in two groups were both given with trimebutine maleate tablets treatment

and Tongxie Anpi decoction was added in the treatment group. Therapeutic course was 4 weeks for both groups. Changes in curative effect of traditional Chinese medicine (TCM) syndrome and TCM symptom scores were observed for both groups. Serum levels of 5-HT and CGRP of patients in two groups were observed before and after treatment. Result: Total effective rate of TCM syndromes was 87.5% in treatment group

superior to 65.0% in control group (P<0.05). In comparison of TCM symptom scores before and after treatment in two groups

differences were statistically significant except bowel distress and mucous stool in control group (P<0.05

P<0.01)

and improvement of diarrhea

abdominal pain

abdominal distension

bowel distress and mucous stool in treatment group was superior to that in control group (P<0.05

P<0.01). Serum levels of 5-HT and CGRP in two groups were significantly decreased after treatment (P<0.05

P<0.01)

and decrement of serum levels of 5-HT and CGRP was significantly larger in treatment group than that in control group (P<0.05). Conclusion: Tongxie Anpi decoction combined with Trimebutine Maleate tablets has clinical effect in treating diarrhea-predominant irritable bowel syndrome with hepatic stagnation and splenic deficiency

and can obviously improve the patients' symptoms. Mechanism may be associated with reducing patients' serum levels of 5-HT and CGRP.