The pharmacological effect of an intermittent therapy with RMP in high dosage (30 mg/kg) on the liver function tests has been studied in 100 African patients. A temporary increase of the serum levels of total and direct bilirubin above the normal values has been observed in the majority of the patients on the day of drug administration. However, no signs of alteration of the liver function (bilirubin, SGOT, SGPT) were apparent 48 h after four RMP administrations in high dosage on alternate days during the first week, nor after 10 weeks of weekly intermittent therapy, even in patients with slightly disturbed liver function before treatment. Therefore, this type of intermittent therapy may be considered as raelly save.