Nifedipine, a calcium channel blocking drug with vasodilating action in both systemic and coronary arterial beds, was administered to 79 patients with a variety of ischemic heart diseases. Forty-five variant angina patients given a mean daily dose of 78 mg experienced a reduction from 2.6 to 0.28 attacks per day (p<0.001), confirmed by in-hospital ergonovine testing (22 patients) and outpatient 24-hour Holter monitoring (28 patients). Twenty-one stable post-acute myocardial infarction patients given a single 20 mg oral dose showed a significant (p<0.001) decrease in mean arterial pressure and systemic vascular resistance, accompanied by a significant (p<0.01) increase in cardiac index and heart rate, most noticeable in the patients with the worst ventricular function. Symptoms were relieved in nine of 13 patients with class III and IV refractory angina pectoris when nifedipine 40-80 mg was added to nitrate and beta blocker therapy. Of angina patients, 40% experienced mild side effects, but only 3% were forced to stop therapy due to peripheral edema. No serious hemodynamic or electrocardiographic toxicity occurred. Precautions should be taken if hepatic enzyme abnormalities or reflex tachycardia develop which may worsen angina. Diltiazem and verapamil have different hemodynamic effect and can be used advantageously in some clinical circumstances.