Chitosan has attracted much attention as a biomedical material, owing to its unique biological activities. In this study, hepatoprotective effect of beta-chitosan obtained from the gladius of squid Sepioteuthis lessoniana was studied against carbon tetrachloride (CCl4)-induced oxidative stress and liver injury in rats. The rats that received beta-chitosan along with the administration of CCl4 showed significantly decreased plasma and tissue alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities and total cholesterol, triglyceride (TG) and free fatty acid (FFA) contents, whereas the treatment with beta-chitosan alone markedly increased rat hepatic and circulatory superoxide dismutase (SOD), catalase and glutathione peroxidase (GPx) and reduced glutathione (GSH) levels and decreased the malondialdehyde level. Histopathological observations recommended the marked hepatoprotective effect of beta-chitosan. The CCl4-induced alterations on circulatory and hepatic antioxidant defence system were normalised by beta-chitosan, and it could be concluded that the hepatoprotective effect of chitosan may be due to its antioxidant and antilipidemic property. Therefore, beta-chitosan could be considered as antihepatotoxic agent.