The effects of postischemic reperfusion were investigated in 14 isolated rabbit hearts in Langendorff preparation. Seven were controls and the others were reperfused with a sodium 7.5% and dextran 60 (60,000 MW) solution diluted with Krebs-Henseleit buffer to a sodium concentration of 150 mEq/l. The incidence of arrhythmias was lower in this group (p = 0.034). Coronary flow was higher than in controls (p = 0.035), the levels of isoenzyme MB of creatine kinase were lower than in controls (p = 0.035), myocardial water content was also lower (p = 0.047), and histological damage was reduced (p = 0.018). It was concluded that early reperfusion with 7.5% sodium chloride, 6% dextran 60 solution has a protective effect in the treatment of cardiac reperfusion injury.