The consumption of diets rich in plant foods are associated with a reduced risk of cardiovascular diseases. This study was aimed to evaluate the role of S-allylcysteine (SAC) in isoproterenol (ISO)-induced myocardial infarction (MI) in rats. Subcutaneous injection of ISO (150 mg/kg) to Wistar rats showed a significant decrease in the activities of marker enzymes such as creatine kinase, lactate dehydrogenase, aspartate and alanine transaminases in heart and a significant increase in the levels of thiobarbituric acid reactive substances and lipid hydroperoxides in plasma and heart. ISO-induced rats also showed a significant decrease in the activities of superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase and glutathione S-transferase in heart and the levels of glutathione and ascorbic acid in plasma and heart. Oral administration of SAC (100 and 150 mg/kg) to ISO-treated rats daily for a period of 45 days caused a significant increase in the activities of marker enzymes and improved the antioxidant status by decreasing lipid peroxidative products and increasing the activities of antioxidant enzymes and the levels of nonenzyomic antioxidants. Administration of SAC to normal rats did not show any significant effect. Histopathological findings of the myocardial tissue showed a protective role of SAC in ISO-treated rats. The effect at a dose of 150 mg/kg of SAC was more pronounced than that of the dose 100mg/kg and brought back all the parameters to near normal. The effect exerted by 100 mg/kg of SAC was similar to that of alpha-tocopherol (60 mg/kg). The results of our study show that SAC possesses antioxidant activity in ISO-induced experimental MI.