The use of digitalis in acute myocardial infarction remains controversial because of disagreement regarding the electrophysiologic, hemodynamic, and metabolic risks and benefits. However, there is no convincing evidence of an increased incidence of arrhythmias following digitalis therapy. Direct measurement of left ventricle function shows improvement of impaired left ventricular performance. The increased metabolic cost of enhanced inotropy following digitalis is countered by reductions in left ventricular end-diastolic pressure and volume, especially when left ventricular failure is present. Extension of infarct size shown in the dog after administration of digitalis may occur only in that experimental model or only if cardiac failure is absent. We conclude that digitalis may be recommended following acute myocardial infarction if the usual indications, supraventricular tachyarrhythmias or cardiac failure, are present.