Abstract: Objective To study the role of Xiaoyaosan powder in increasing sensitivity and reducing side effects of adjuvant radiotherapy in breast cancer patients with liver stagnation and spleen deficiency. Methods From February,2015 to January,2016,88 breast cancer patients with liver stagnation and spleen deficiency in our hospital were enrolled and randomly divided into observation group and control group with 44 cases in each group.After the operation,the control group received the conventional radiotherapy,while the observation group received additional TCM Xiaoyaosan powder based on the conventional treatment.The immunological indexes,inflammatory indexes,liver function indexes and adverse reaction were compared between the two groups. Results Before the treatment,there was no significant difference in CD3⁺ and CD8⁺ levels between the two groups.After the treatment,the CD4⁺ level of the treatment group was (41.2±2.9)%,which was significantly higher than the control group (34.1±2.7)%,the difference was statistically significant (P<0.05).After the treatment,IL-1,IL-6 and TNF-α levels in both groups were significantly improved,and IL-1,IL-6 and TNF-α levels in the observation group were significantly lower than those in the control group,the differences were statistically significant (P<0.05).The incidence of blood system disease,gastrointestinal toxicity and radiation dermatitis in the observation group were 6.82%,4.55% and 2.27%,respectively,which were lower than those in the control group,the differences were statistically significant (P<0.05). Conclusion TCM Xiaoyao powder in the treatment of breast cancer patients with liver stagnation and spleen deficiency can effectively improve the immunologic function of patients,reduce inflammation,and decrease the side effects of radiotherapy,with a good safety.