Summary :Experimental autoimmune myocarditis (EAM) in rats is a T-cell-mediated disorder and has been shown to involve immune imbalance. The aim of this study was to examine the immunomodulatory effects of 3-hydroxy-3- methyl-glutaryl coenzyme A reductase inhibitor, atorvastatin, on the expression of MHC class II molecules in the myocardium of rats with EAM, and to examine its therapeutic potential for EAM. EAM was induced in Lewis rats by injection of porcine cardiac myosin. High-dosage (10 mg/kg per day) or low-dosage (1 mg/kg per day) atorvastatin or vehicle was given orally for 3 weeks. On day 21 after immunization, echocardiography was carried out and the severity of myocarditis was evaluated by histopathologica