To observe the clinical efficacy of the method of regulating liver and spleen on treating irritable bowel syndrome of diarrhea pattern. Methods:A total of 97 IBS-D patients were randomly divided into two groups. One group received traditional Chinese medicine treatment which has effect of regulating liver and spleen; and the other group received pinaverium bromide. Both groups received the treatment for 4 weeks. We followed up the patients for 3 months after treatment to observe the symptoms and the curative effect. Results: The symptoms of both groups showed obvious improvement than before the treatment when it was observed after 2 weeks and 4 weeks of treatment, and 1 month and 3 months after treatment. There were statistical differences (P<0.05). After 4 weeks of treatment, the symptom reduction value of regulating liver and spleen group was better than that of pinaverium bromide group with statistically significant difference (P<0.05); the total effectiveness of the regulating liver and spleen group was 92.2% and pinaverium bromide group was 69.6%, it indicated that regulating liver and spleen group was better than the pinaverium bromide group and the difference was statistically significant (P<0.05). In the respect of improving the major symptoms such as the number of defecation and character of stool, the regulating liver and spleen group was superior than pinaverium bromide group, and the difference was statistically significant (P<0.05). Conclusion:The prescription of regulating liver and spleen has a good clinical curative effect on treating IBS-D.