To evaluate the clinical effect by administration of recombinant human granulocyte-stimulating factor (rhG-CSF) post chemotherapy in non-Hodgkin malignant lymphoma (NHL), 17 patients with NHL were subjected to this study. Administration of rhG-CSF ameliorated the decrease in absolute neutrophil counts after the cytotoxic chemotherapies and activated neutrophil functions in active oxygen product and expressions of adhesion proteins. To consistent with these results, rhG-CSF administrations post cytotoxic chemotherapy were effective for reducing infection complications associated with neutropenia. Furthermore, administration of rhG-CSF increased peripheral hematopoietic progenitor cells, thus suggesting promising therapeutic potential for autografting. Recently, it has been reported that blood neutrophils may synthesize mRNA and proteins important in inflammation including various cytokines such as IL-1, IL-6, TNF-alpha and IFN-alpha, but, administration of rhG-CSF showed no obvious effect on the level of either IL-1, IL-6, TNF-alpha or IFN-alpha in sera, and furthermore, the in vitro stimulation by rhG-CSF induced no significant production of these cytokines and expressions of TNF-alpha and IFN-alpha mRNAs. Finally, we studied on anti-tumor effect of administration of rhG-CSF in CDF1 mice inoculated with syngeneic lymphoma cells. rhG-CSF infusion suppressed the liver metastasis and prolonged the overall survival, thus suggesting the hypothesis that use of rhG-CSF in some patients with NHL might control the disease through stimulating both production and functional activation of neutrophils.