Pravastatin sodium was administered orally to cynomolgus monkeys at dosage levels of 50, 100, 200 and 400 mg/kg/day for 5 successive weeks. Five animals of 200 mg/kg and 400 mg/kg dose groups were sacrificed during the study period, because these animals deteriorated in general condition and/or showed remarkable changes in serum biochemical examination. Pathological examination revealed hepatic and/or renal disturbance in these animals. These changes are thought to be the cause of deterioration of general condition or changes in serum biochemical examination. All other animals were terminated at the end of the study period. In the animals of the 100 mg/kg dose group, only one animal showed hepatic and renal disorder similar in nature to the changes in the animals sacrificed during the study period. No animals in the 50 mg/kg dose group showed toxic findings in any examination.