Crl:CD1 (ICR) BR mice were colonized in the gastrointestinal (GI) tract with Candida albicans. This strain was susceptible to ketoconazole (MIC=0.25 microg/ml), itraconazole (minimum inhibitory concentration, MIC=0.25 microg/ml), and fluconazole (MIC=4 microg/ml). Subsequently the animals received monotherapy with ketoconazole by mouth (equivalent to human dose of 2.9 mg/kg/day), or itraconazole by mouth (equivalent to human dose of 2.9 mg/kg/day), or fluconazole either subcutaneously (equivalent to human dose of 2.2 mg/kg/day), or by mouth (equivalent to human dose of 2.2 mg/kg/day), for 10 days. Quantitative stool cultures at the end and one week after the end of treatment revealed that all three azoles caused a small and statistically non significant reduction of C. albicans concentration in the stools. The different route of administration of fluconazole did not produce different results. In conclusion, these azoles, used at the present doses and schedules, have minimal effect on murine GI colonization by this strain of C. albicans which is susceptible but with rather increased MICs.