The current investigation was carried out to find out the anticancer activity of the methanol extract from Buplerum falcatum against cancered ICR mouse and cancer cell lines such as J774A.1 and L1210 cells. Extract of Buplerum falcatum displayed the considerable augmentation(134%) of the survival of ICR mouse bearing Sarcoma 180 cancer. In addition, the cytotoxic effects of methanol extract of Buplerum falcatum against J774A.1 cells and L1210 cells were found to show $IC_{50}$ values of $57.3;{mu}g/ml$ and $54.6;{mu}g/ml$, respectively. In contrast to such cytotoxicity against cancer cells, the extract exerted only meagre toxicity against normal lymphocytes. The increased generation of $O_2^-$ and the considerably increased activities of super-oxide dismutase(SOD) and glutathione peroxidase(GPx) of both J774A.1 cells and L1210 cells in the presence of Buplerum falcatum extract implied that the observed cytotoxicities may have resulted from the detrimental effect of reactive oxygen species(ROS) evoked by Buplerum falcatum extract on the cancer cells.