The calcium antagonist bepridil (bepridil monohydrochloride monohydrate, Org 5730, Cordium) was investigated in comparison with verapamil in a double-blind cross-over design in patients with angina pectoris. Exercise parameters, frequency of anginal attacks, consumption of nitroglycerin and subjective preference were analysed for 36 patients. The exercise capacity, estimated by exercise time and total work load during standard bicycle testing, was significantly more improved with bepridil treatment than with verapamil treatment. No significant differences were observed in frequencies of anginal attack, consumption of nitroglycerin and subjective preference. Side effects were mild and equally divided over both treatment groups.