Dimethyl sulfoxide (DMSO) is an organic compound widely used as solvent in biological studies and as vehicle for drug administration. DMSO has been shown to possess several biological effects, including antioxidant, anti-inflammatory, antinociceptive effects, and it has been proposed to be therapeutic in several disorders, such as gastrointestinal diseases, rheumatologic diseases, and for the treatment of several manifestations of amyloidosis. To better define the biological profile of DMSO, we investigated its effect on an in vivo model of acute myocardial infarction in rats, caused by left anterior descending coronary artery ligation. Our results show that pretreatment of rats with intraperitoneal (ip) DMSO (500 microL/Kg) for 3 consecutive days before left anterior descending coronary artery ligation significantly (P < 0.05) reduced cardiac damage from 18.75 +/- 4.88% (n = 12) to 4.46 +/- 2.01% (n = 8); serum levels of troponin I from 29.35 +/- 12.32 ng/mL (n = 8) to 2.95 +/- 1.32 ng/mL (n = 4); and serum levels of myoglobin from 46.86 +/- 10.35 ng/mL (n = 7) to 13.75 +/- 0.85 ng/mL (n = 4). Our data demonstrate that DMSO has a protective effect in a model of acute myocardial infarction in rats.