To explore clinical efficacy of simo decoction in irritable bowel syndrome due to liver and spleen disharmony.Methods:A total of 129 patients with irritable bowel syndrome due to liver and spleen disharmony were selected from February 2016 to May 2016 in our Hospitals.According to the random distribution, all patients were divided into observation group of 65 cases and control group of 64 cases.The control group received lactulose and trimebutine maleate, and the observation group was given simo decoction on the basis of control group.TCM syndrome score was used to assess curative effects and scores of TCM syndrome.The adverse events of two groups were observed.Results:The effective rate of TCM syndrome in observation group was significantly higher than the control group, which was statistically significant (P<0.05); Before treatment, stomachache, diarrhea, dark red tongue, thin white fur, pulse string and total score of observation group and control group was basically the same, without significant difference (P>0.05); For 7 d after treatment, stomachache, diarrhea, dark red tongue, thin white fur, pulse string and total score of observation group was significantly lower than the control group, which was statistically significant (P<0.05); No adverse reactions occurred in two groups during treatment.Conclusion:Lactulose and trimebutine maleate are commonly used drugs for treatment of irritable bowel syndrome.Based on lactulose and trimebutine maleate, simo decoction in the treatment of irritable bowel syndrome due to liver and spleen disharmony is safe and can improve curative effect, which is worthy of clinical application.