Doxaminol is a recently developed beta-sympathomimetic agent, which has shown promising positive inotropic activity in experimental animal models. It is a dibenzoxepine derivative. In normal volunteers, doxaminol exhibits effects on noninvasive cardiological indices similar to those observed after cardiac glycosides. After single-dose application of doxaminol in cases of congestive heart failure, cardiac output and stroke volume increased, heart rate increased slightly, pulmonary and systemic arterial pressure remained constant, and peripheral vascular resistance decreased. No arrhythmias appeared, but one patient suffered an attack of angina.