Carnosine (beta-alanyl-L-histidine) is a dipeptide with antioxidant properties. Oxidative stress has been proposed to be involved in thioacetamide (TAA)-induced liver cirrhosis in rats, that is similar to human disease. In this study we aimed to investigate the role of carnosine on the development of TAA-induced cirrhosis. 200 mg TAA/kg body weight has been given i.p. twice a week for three months to female wistar rats. Another group received same dose of TAA in the same pattern plus 2 g carnosine/L of drinking water for three months. TAA administration resulted in hepatic fibrosis, significant increases in plasma transaminase activities as well as hepatic hydroxyproline and lipid peroxide levels, while liver glutathione (GSH) and superoxide disinutase (SOD) and glutathione peroxidase (GSH-Px) protein expressions and activities decreased. Carnosine was found to behave as an antioxidant reducing malondialdehyde (MDA) and diene conjugate (DC) levels although it was not effective on increased transaminase activities and decreased antioxidants. It also did not affect the histopathological changes observed in TAA group. Thus our findings indicate that carnosine appears to attenuate peroxidation as an antioxidant itself but does not seem to prevent the development of TAA-induced cirrhotic process. (C) 2009 Elsevier Inc. All Fights reserved.