It is well known that recombinant human granulocyte increases dramatically the number of granulocytes in peripheral blood. It is interesting to see if G-CSF enhances the functions of neutrophil since the neutrophil is one of the most important factors of host defence mechanism against infections. In this study, we have demonstrated that G-CSF induced the polarization of neutrophil while it could not be chemoattractant for the cell. Polarization is considered to be the initial reaction of chemotaxis. Therefore, G-CSF might enhance the defence effect of the neutrophils+ to infections in this point.