Objective: To study Ginseng polysaccharide’s effect on proliferation of human promyelocytic leukemia cell line（HL-60）and modulation of human granulocytopoiesis and monocytopoiesis. Methods: Using the techniques of cell culture ex vivo

flow-cytometry

immunocytochemistry

the effects of GPS on the proliferation of human promyelocytic leukemia cell line(HL-60) and human granulocytopoiesis and monocytopoiesis were observed. Results: GPS can significantly inhibit the proliferation of HL-60 ex vivo

the inhibitory effect is concerned with the concentration. The higher the concentration of GPS

the greater the proliferation inhibited; GPS may prevent HL-60 from the silent phase (G0) entering the active proliferative phase(S/G2+M)

thus prohibit the synthesis of DNA; GPS probably can not induce HL-60 to differentiate into mature granulocytes or monocytes under our experimental conditions. Conclusion : GPS not only can promote the colony formation of CFU-GM but also can inhibit the proliferation of HL-60 by cytotoxic effect or by preventing HL-60 from G0 phase entering S/G2+M phase.