We have studied the efficacy and safety of recombinant human granulocyte-macrophate colony-stimulating factor (rhGM-CSF, leucomax) to treat leukopenia and neutropenia induced by chemotherapy with regimen CE (Carboplatin, Etoposide) and regimen CEA (Carboplatin, Etoposide, Adriamycin) on patients in a randomized comparative, cross-over clinical trial. Twenty-one patients enrolled were randomly divided into A(n = 8) and B group(n = 13). Each patient received two cycles of treatment. In group A, chemotherapy and rhGM-CSF were given in the first cycle and in the second cycle only chemotherapy was given. In group B, only chemotherapy was given in the first cycle and chemotherapy and rhGM-CSF were given in the second cycle. The results showed that rhGM-CSF significantly increased the total white cell count (WBC) and absolute neutrophil count (ANC) at nadir, decreased the incidence of leukopenia and neutropenia, and shortened the duration of leukopenia with WBC < 4.0 x 10(9)/L and ANC < 2.5 x 10(9)/L, and the number of days for recovery to WBC > 4.0 x 10(9)/L and ANC 2.5 x 10(9)/L. However, rhGM-CSF displayed little effect on platelets. The main side-effect of rhGM-CSF was fever (43%), as well as skin rashes and influenzalike symptoms.