This study was aimed to explore the factors impacting on effect of the recombinant human granulocyte colony-stimulating factor (rhG-CSF) in mobilizing and collecting peripheral blood stem/progenitor cells (PBSPC) from healthy donors, and to determine the optimal time for PBSPC harvest. A mobilization course in 431 healthy donors was retrospectively studied and the factors influencing the efficacy of mobilization were analyzed. The normal donors underwent leukapheresis for PBSPC collection in multicentres after mobilization with G-CSF administered. A variety of items analyzed included donor age, sex, weight, body mass index (BMI), daily G-CSF dose and schedule of G-CSF administration. The results showed that G-CSF was administered subcutaneously at median 5.7 microg/kg for mobilization for 3 - 5 days, The median number of peripheral blood mononuclear cells (PBMNC) count of per kg recipient weight was 9.57 x 10(8) and CD34(+) cells per kg recipient weight was 4.91 x 10(6) after a median of 1.7 leukapheresis. The side effects were mild and well tolerated. By univariate analysis, BMI, daily G-CSF dose and schedule of administration were significantly correlated with the yield of PBMNCs, CD34(+) cells. The best apheresis yields of PBMNCs and CD34(+) cells were achieved on day 5 after treatment with rhG-CSF. Because the narrow range and low dose of rhG-CSF administration, there were minor effects of rhG-CSF dose compared with schedule of administration. It is concluded that mobilization and leukapheresis are safe in healthy donors and that the low dose of rhG-CSF in 5-day administration are probably optimal for donor management.