Abstract: Administration of an anti-inflammatory steroidal drug-Prednisolone- (0.85 mg/kg body weight, daily for 10 days) to adult toads Bufo tibamicus resulted in suppression of the function of the adrenal gland, as shown by a significant increase in the lipid droplets, autolysis of mitochondria and disorganization and degranulation of rER in the steriodogenic cells. Furthermore, chromaffin cells (catecholamines secreting cells), showed a marked decrease in the number of chromaffin granules and degenerative changes in the nuclei. These serious side effects should be taken into consideration when using this drug.