The aim of this work was to evaluate the effect of the antioxidant stobadine on ischemia/reperfusion-induced injury of the isolated rat heart. Experiments were performed according to Langendorff. Ischemia was induced by stop-flow lasting 30 minutes and the duration of repefusion was 30 minutes. Reperfusion of the ischemic heart induced dysrhythmias, with the most severe ones occurring in the first minutes of reperfusion. A significant increase in coronary perfusion pressure was observed starting after 15 min of reperfusion. Stobadine (10(-6) M applied 3 minutes before onset of ischemia and during reperfusion) prevented the deleterious effects to develop fully. The protective effect of stobadine observed in our experiments seems to be a consequence of its antioxidant properties.