To study the effects of Yiqi Wenyang method combined with cisplatin on T regulatory cell (Treg) of Lewis lung cancer mice.Methods:After 40 inbred C57BL/6 male mice with Lewis lung cancer cell transplanted subcutaneously were established,They were randomly divided into model group,traditional Chinese medicine group,cisplatin group and combined drug group,10 in each group,fed in single cage.The model group was given 0.4 mL saline for 12 days;In the traditional Chinese medicine group,0.4 mL of traditional Chinese medicine solution was infused into the stomach for 12 days (20 g crude drug/kg);In cisplatin group,0.2 mL cisplatin solution was intraperitoneally injected,and cisplatin solution (4 mg cisplatin/kg) was intraperitoneally injected on the first day,the third day and the fifth day respectively;In the combined group,0.4 mL traditional Chinese medicine solution was infused into the stomach for 12 days (20 g crude drug/kg),and 0.2 mL cisplatin solution (4 mg cisplatin/kg) was injected intraperitoneally on the first day,the third day and the fifth day.After 12 days of drug intervention,the proportion of Treg cells in spleen tissue of mice in each group was detected by flow cytometry.Results:the results of flow cytometry showed that the treatment of Yiqi Wenyang method could significantly reduce the spleen Treg cells of Lewis lung cancer mice.Compared with the model group,the number of the proportion of CD4+CD25+ Treg cells and the proportion of CD4+CD25+Foxp3+ Treg cells in spleen tissue of mice in the traditional Chinese medicine group,cisplatin group and combination group were significantly reduced (P<0.05).Conclusion:the method of Supplementing Qi and warming yang can inhibit tumor by reducing the level of Treg cells and enhancing the anti-tumor immune response.