Background Hematopoietic growth factor(HGF)is indispensable to hematopoiesis in the body. The proliferation and differentiation of hematopoietic cells must rely on the existence and stimulation of HGE. This study investigated the effect of catechin, an active component extracted from Spatholobus suberectus Dunn (SSD), on bioactivity of granulocyte-macrophage colony-stimulating activity(GM-CSA), burst-promoting activity(BPA)and megakaryocyte colony-stimulating activity(MK-CSA)in spleen condition medium(SPCM)of mice to clarify the hematopoietic mechanism of catechin and SSD. Methods Spleen cells of mice were separated and spleen condition medium (SPCM)was prepared from spleen cell culture. Bone marrow cells of mice were separated and cultured in a culture system including 10%(v/v)SPCM(induced by catechin in vivo or ex vivo)for 6 days. Granulocyte-macrophage colony forming units(CFU-GM), erythrocyte burst-colony-forming units(BFU-E)and megakaryocyte colony-forming units(CFU-Meg)formation were employed to assay the effects of different treatment on the bioactivity of GM-CSA, BPA and MK-CSA in SPCM. Results SPCM induced by 1 00 mg/L catechin ex vivo could promote the growth of CFU-GM, BFU-E and CFU-Meg, which indicated that catechin could stimulate the production of GM-CSA, BPA and MK-CSA in SPCM. SPCM prepared at the fourth day of spleen cell culture showed the best stimulating activity. The bioactivity of GM-CSA, BPA and MK-CSA in the SPCM prepared after intraperitoneally injecting catechin into mice was also increased. The number of CFU-GM, BFU-E and CFU-Meg gradually increased as the dose of catechin increased and the time of administration prolonged. CFU-GM, BFU-E and CFU-Meg of the high-dose catechin group were significantly higher than those of the control group (P＜0.01)and reached the maximum at the seventh day after administration. Conclusions This study suggests that catechin extracted from the active acetic ether part of Spatholobus suberectus Dunn can regulate hematopoiesis by inducing bioactivity of GM-CSA, BPA and MK-CSA in SPCM of mice. This may be one of the mechanisms for the hematopoietic-supportive effect of catechin and Spatholobus suberectus Dunn.