Crude extracts of soybean (SBA) was prepared by steeping of the bean in normal saline and precipitating with ammonium sulfate. This extract was used to fractionate spleen hematopoietec cells and immunogenic cells. Groups of mice received irradiation of 850 rads. The survival rate of control group was 1/20. while that of mice in which SBA fractionated allogeneic splenic cells were transplanted was 13/19. and transplantation of non-fractionated splenic cells only yielded a survival of 4/20 by the end of 30 days. The mean survival time of animals receiving spleen cell agglutinated by SBA was 27.0?7.5 days. that of hemogenous spleen cell 21.6?7.5 days. and the control 9.2?6.2 days.In vitro, the spleen cells agglutinated once by SBA could eliminate 82.2% of T cells, and those agglutinated twice by SBA could eliminate 93.1% of T cells. The cytotoxic index was greatly reduced after two agglutinations by SBA. Using agar diffusion chamber method, the production rate of colonies of granulopoietic stem cells among spleen cells was determined. It was found that CFU-C/105 of the SBA agglutinated fraction of spleen cell was enhanced 2.8-fold over that of non-agglutinated fraction.Our preliminary result demonstrated that crude SBA can fractionate hematopoietic cells, which in turn became capable of eliminating immunogenic cells and raise the survival rate of irradiated mice, as efficiently as pure SBA.