The purpose of this research was to investigate the effects of Kami Kwiryong Tang (KKT) on the immune cells in BALB/c mice. KKT (500mg/kg) was administerd p.o. once a day for 7 days. KKT decreased the proliferation of thymocytes, but did not affect the proliferation of splenocytes. KKT enhanced the subpopulation of Th (CD4+CD8- single positive cells) cells in splenic T-lymphocytes, but decreased the subpopulation of Th cells in thymocytes. KKT enhanced the production of ${gamma}$-interferon and interleukin-2, but did not affect the production of interleukin-4 in mice serum. KKT did not affect the production of nitric oxide, but enhanced the phagocytic activity in peritoneal macrophages. These results suggest that KKT is a potent prescription on immune response via the production of cytokines from splenic Th1 cells and the increase of phagocytic activity in vivo.