Abstract：Objective：To observe the clinical effect of Tongxie Yaofang for diarrhea- type irritable bowel syndrome(IBS). Methods：A total of 80 patients with diarrhea-type IBS were selected and divided into the control group and the observation group according to the random number table method， 40 cases in each group. Both groups were given routine guidance on diet and lifestyle；the control group was additionally given pivecuronium bromide tablets and the observation group was additionally given Tongxie Yaofang. The clinical effect ， the levels of brain-derived neurotrophic factor(BDNF) ， 5- hydroxytryptamine(5- HT)， neuropeptide(NPY)， interleukin- 8(IL- 8)， interleukin- 10(IL- 10) and interferon- γ(IFN- γ) in serum in the two groups were detected. Results：The total effective rate was 97.50% in the observation group，higher than that of 85.00% in the control group，the difference being significant(P＜0.05). After treatment，the times of abdominal pain， the times of diarrhea，the times of bowl movement and the scores of stool traits and symptoms were all decreased in the two groups when compared with those before treatment，and the above indexes in the observation group were lower than those in the control group(P＜0.05). After treatment，the levels of BDNF and NPY in serum in both groups were increased when compared with those before treatment， and 5- HT levels were decreased(P＜0.05)； the levels of BDNF and NPY in the observation group were higher than that in the control group，5-HT level was lower than that in the control group(P＜0.05). After treatment，the levels of IL-8 and IFN-γ in both groups were lower than those before treatment，and the two levels in the observation group were lower than those in the control group(P＜0.05). The IL-10 levels in the two groups were increased when compared with those before treatment，and the IL-10 level in the observation group was higher than that in the control group(P＜0.05). Conclusion： Tongxie Yaofang can effectively relieve the clinical symptoms of diarrhea- type IBS， maintain the level of BDNF in serum，and inhibit the inflammatory responses.