Cytokine treatment is used increasingly for granulocyte and stem cell collection from healthy donors. This manuscript reviews the current literature on recombinant human granulocyte colony-stimulating factor (rhG-CSF)-induced expansion of circulating leukocytes, lymphocyte subsets, monocytes and granulocytes. There is a particular focus on the mobilization and peripheralization of stem cells, including quantitative and and kinetic aspects, the clonogenic potential of mobilized stem cells, and the rhG-CSF dose dependency of mobilization efficiency, RhG-CSF given to healthy individuals also affects the cytokine profile of mobilized and collected T cells, which after allotransplantation, might positively affect the incidence and severity of GVHD. Short- and long-term side-effects of rhG-CSF given to healthy individuals are discussed together with a consensus reached on safety considerations for healthy blood stem cell donors.