An aqueous extract of Prunus africana (Hook. f.) Kalkm. (syn. Pygeum africanum) (Hook. f.) (Rosaceae) was administered daily at dosage rates of 10, 100 and 1,000 mg/kg body mass to randomized groups of Sprague Dawley rats. The extract caused a moderate rise in plasma alanine aminotransferase and creatine kinase mainly at rates of 1,000 mg/kg body mass, but it did not cause any significant variations in haematological parameters or in plasma levels of total proteins, albumin, aspartate aminotransferase, alkaline phosphatase and blood urea nitrogen at the dosage levels used. There were no overt clinical signs in any of the rats. It was concluded that the extract may contain components that are mildly toxic to the liver and heart of rats after repeated daily oral administrations of 1,000 mg/kg body mass.