This study was designed to observe the dynamic changes in the immune functions of mice bearing the S180 tumor at different day-points after treatment with a Chinese medicine recipe:"YILIUYIN",and to explore its immunologic mechanisms.In this study,BALB/c mice were inoculated with S180 tumor cells subcutaneously in the right axilla,and after 24 hrs,"YILIUYIN" was adminstrated orally in the experimented group of mice,and the mice receiving cold water was taken as control.Mice were killed at 0,10,20,30 and 40 days points,and the body weight and the tumor weight were recorded.The NK cell activity,transformation and IL-2 activity induced by(ConA) were detected by MTT assay,and the percentages of CD4~+ and CD8~+ cells were determined and analyzed by FACS.It was found that "YILIUYIN" could inhibit the growth of the S180 cell-transplanted tumor in mice,and reversed the inhibiting effect,induced by the transplanted tumor on the immune functions of murine splenocytes,including the killing activity of NK cells,proliferative activity induced by ConA,the production of IL-2 by splenocytes as well as the percentages of CD4~+ and CD8~+ cells,and this reversing effect on immune functions was in a time-dependent manner.It is evident that "YILIUYIN" can up-regulate the immune functions inhibited by the S180 tumor cells and exhibits anti-tumor effect in vivo.