To investigate the effect of ginsenosides (GS) on proliferation and differentiation of human CD 34 + stem/progenitor cells. Methods: CD 34 + hematopoietic progenitor cells were isolated from umbilical cord blood by using the immune beads sorting system. The cells were exposed to GS of different concentrations in both liquid culture and semi-solid culture, and the elevation rate on proliferation of CD 34 + stem/progenitor cells and colony formation were estimated. The cells were marked with monoclonal antibody and the marker was examined by flow cytometry after incubated with GS for 14 days. Results: GS (5-50μg/ml) could raise the colony production rate of BFU-E、CFU-E、CFU-GM、CFU-GEMM by (87 6±2 6)%、(63 3±2 8)%、(58 0±3 1)% and (96 3±5 5)% respectively (all P<0 01), and the best effect in improving cell proliferation of CD 34 + cells in vitro was obtained when the concentration of GS was 25 μg/ml. After incubation with GS for 14 days, number of CD 33 + cells was increased by GS in a dose-dependent manner with a peak increasing rate at 200 μg/ml. In the presence of GS 50 μg/ml, CD 15 + cells were reaching the peak. Number of CD 71 +and G-A + cells increased only when the concentration of GS was 25 μg/ml. Conclusion: GS could not only promote the proliferation but also induce the differentiation of CD 34 + hematopoietic stem/progenitor cells, GS may play the role by cooperating with hematopoietic growth factor, and by its growth factor-like function in the regulation of hematopoiesis.