Piprofurol is a benzofuran chalcon derivative. It is a calcium channel blocker. Piprofurol inhibited in a concentration-dependent manner the calcium-induced contractions in isolated potassium depolarized preparations of rat aorta and relaxed the K+-induced contraction of the dog coronary artery and the rabbit basilar artery. Piprofurol also inhibited noradrenaline-induced vascular smooth muscle contractions but the antagonism was clearly noncompetitive and the contractions induced were altered by concentrations two orders of magnitude higher than the concentration inhibiting calcium-induced contractions. Piprofurol exerts a negative inotropic effect on guinea-pig papillary muscle. These effects suggested a potentially anti-ischemic activity. This is confirmed in anaesthetized dogs, where piprofurol reduced the epicardial ST-segment elevation following coronary artery occlusion, and in isolated heart preparations, where it decreased the leakage of LDH during periods of anoxia and reoxygenation. Piprofurol is a coronary vasodilator and antihypertensive agent.