Low-dose, subcutaneous recombinant human granulocyte colony-stimulating factor (rHuG-CSF, Lenograstim) was administered to 40 cancer patients (17 men, 23 women) enrolled from two medical centers to verify its clinical effectiveness and safety. The patients' mean age was 50.3 +/- 14.9 years. In this study, there were 20 patients with non-Hodgkin's lymphoma, 10 with breast cancer and 10 with various other solid tumors. The patients first received a course of chemotherapy without rHuG-CSF (control cycle). All patients had at least one episode of neutropenia or leukopenia during the control cycle. rHuG-CSF (2 micrograms/kg/day) was given subcutaneously for 10 days during the study cycle starting on the fourth day of chemotherapy. The nadirs of absolute neutrophil counts (ANC) were 1.8 +/- 0.25 x 10(9)/L and 0.27 +/- 0.05 x 10(9)/L for the rHuG-CSF cycle and pre-rHuG-CSF control cycle, respectively. The number of days of ANC < 1 x 10(9)/L were 1.03 +/- 0.29 and 7.38 +/- 0.58 for rHuG-CSF and control cycles, respectively. The duration from nadir to recovery of ANC (> or = 2 x 10(9)/L) was 9.68 +/- 1.15 days in the rHuG-CSF cycle, vs 22.53 +/- 1.03 days in the control cycle (p < 0.0001). No patient withdrew from the study. Adverse events were mild, with 12.5% to 40% of patients developing myalgia, general malaise, back pain, anorexia or fever. These side-effects were tolerable in all cases. The biochemical abnormalities were subtle and negligible. rHuG-CSF 2 micrograms/kg/day given subcutaneously for 10 days beginning on the fourth day of chemotherapy is very effective (90%), safe and convenient.