Fluconazole is a triazole antifungal agent used for the treatment of certain superficial and systemic infections which predominantly affect immunocompromised individuals. Force-feeding toads with fluconazole at therapeutic dose level (0.26 mg/toad) for 20 weeks resulted in pronounced alterations of the blood cells of the peripheral blood. Most leucocytes showed irregularities in nuclear configuration, cytoplasmic vacuolation, pleomorphic granules and a paucity of organelles. These alterations are more or less similar to those reported in humans with leukaemia and were comparable to those observed after the administration of the carcinogenic chemical 7,12 dimethylbenz(a) anthracene (DMBA).