Diproteverine is a calcium channel blocking agent. Diproteverine provoked a dose-dependent inhibition of LHRH-stimulated luteinizing hormone release. Diproteverine does not modify mean blood pressure. Diproteverine administered with and without pharmacologic autonomic blockade in the conscious dog causes dose-related depressant effects on sinus node function and atrioventricular conduction without producing significant vasodilatation. Diproteverine caused a redistribution of the available coronary blood flow, to the benefit of an ischemic area of the myocardium. The combination of the reduction in heart rate, to lower cardiac oxygen demand, with the beneficial action on coronary blood flow should result in diproteverinebeing particularly beneficial for the treatment of angina pectoris.