The effects of saponins of panax ginseng and Panax pseudoginseng on the murine bone marrow stem cells were studied by means of spleen colony assay (SCA). It was shown that 10mg/kg Panax ginseng saponins significantly intensified the killing effects of harringtoni-ne on the murine bone marrow nucleated cells and multipotential hemopoietic stem. cells (CFU-S) by intraperitoneal administration. Similar effects failed to be observed when Panax pseudoginseng saponins were used in the same dosage and route of administration as Panax ginseng.