Sa-Mul-Tang(SMT) consist of Rehmanniae Radix Preparata, Paeoniae Radix Alba, Cnidii Rhizoma and Angelicae Gigantis Radix. In L1210 cells-transplanted BALB/c mice, T-lymphocyte apoptosis, $CD8^+T_C$ cells population in thymocyte and nitric oxide production in macrophage were enhanced, but phagocytic activity was decreased. SMT suppressed T-lymphocyte apoptosis and enhanced CD^4+T_H$ cells population, but did not affect nitric oxide production and phagocytic activity in L1210 cells-transplanted mice. In antitumor drugs-injected mice, T-lymphocyte apoptosis was enhanced, but $CD4^+T_H/CD8^+T_C$, cells population and T-lymphocyte proliferation were decreased. SMT suppressed T-lymphocyte apoptosis, and enhanced $CD8^+T_C$ cells population, T-lymphocyte proliferation and phagocytic activity in vincristine-injected mice. These results suggest that SMT enhances T cell-mediated immunity in L1210 cell-transplanted mice, and enhances T cell-mediated immunity and phagocytic activity in vincristine-injected mice.