The studies were conducted to investigate the combined effects of several combined preparation of crude drugs and mitomycin C(MMC). The combined effects on the proliferation of HepG2, A549, KHOS-Np, A431 and HeLa cells were estimated by MTT colorimetric assays. Sa Kunja Tang(SKT), Boyang Hwanoh Tang(BHT) and Hyulbu Choogo Tang(HCT) inhibited the proliferation of A549 and HeLa cell. The inhibitory action of MMC was increased by the combined treatment of SKT and MMC, and Sa Mul Tang(SMT) and MMC, respectively. When the mice were treated by MMC, the number of leukocyte was decreased significantly at the 3rd day, but recovered at the 7th day. In the groups of MMC treated with SKT or HCT, the number of leukocyte was increased significantly that the group of MMC treated only at the 1st and 3rd day. The combined treatment of SKT, SMT, BHT, HCT and MMC retained the spleen weight of mice at the level of normal mice, but decreased the thymus weight of mice. The combined treatment of SKT, SMT, BHT, HCT and MMC increased the number of PFC significantly than the MMC treated group. The combined treatment of SKT, SMT, BHT, HCT and MMC increased the T cell proliferation significantly thant the MMC treated group.