The aim of the present study was to assess the influence of immunomodulation of host defense with recombinant murine granulocyte colony-stimulating factor (rmG-CSF) on intra-abdominal abscesses caused by Candida albicans. Mice received prophylaxis or therapy with 1 microg of rmG-CSF/day in the presence or absence of antifungal treatment consisting of amphotericin B (0.75 mg/kg of body weight/day) or fluconazole (50 mg/kg/day). The number of Candida CFU in abscesses was significantly reduced (P<0.05) in mice receiving rmG-CSF prophylaxis (day -1 or day -1 through 2) compared with controls on day 8 of infection. Administration of rmG-CSF therapy alone (for 5 days starting on day 4 of infection) had no influence on the number of Candida CFU in abscesses. Amphotericin B treatment was significantly more effective than fluconazole treatment (3.41 log CFU/abscesses; 95% confidence interval [CI], 3.17 log CFU/abscesses; 3.65 versus 3.90 log CFU/abscesses; 95% CI, 3.66 log CFU/abscesses, 4.16 log CFU/abscesses; P<0.05). Therapeutic administration of rmG-CSF in conjunction with an antifungal agent showed a tendency towards a further reduction of Candida CFU in abscesses than antifungal treatment only. In conclusion, in this experimental model of intra-abdominal Candida abscesses, rmG-CSF administration did not have a detrimental influence on the course of infection. Amphotericin B treatment was most effective, and additional rmG-CSF therapy did not antagonize the effect of antifungal treatment. In contrast, addition of rmG-CSF therapy to antifungal treatment might further enhance the beneficial effect of the antifungal agent.