Objectives : Yukmi-Jihwang-Tang(YJT) has been used in Oriental Medicine as a drug for tonifying and nourishing yin. So, the purpose of this Study was to investigate effects of Yukmi-Jihwang-Tang extract(YJTE) on the T-lymphocytes and peritoneal macrophages in mice. Methods : YJTE consists of the following components; Rehmaniae Radix Preparata(熟地黃), Dioscoreae Rhizoma(山藥), Corni-Fructus(山茱萸), Hoelen alba(白茯), Moutan Cortex Radicis(牧丹皮), Alismatis Rhizoma(澤瀉). Result : The results of this Study were obtained as follow; The administration of YJTE did not affect T-lymphocytes apoptosis. YJTE decreased sub-population of TH and TC cells, and proliferation of T-lymphocytes too. But YJTE accelerated phagocytic activity and Nitric Oxide(NO) production from peritoneal macrophages in mice. Conclusions : These results suggest that the administeration of YJTE suppresses T-cell mediated immunity, but activates peritoneal macrophages