Seven plants which are used in Turkish folk medicine were studied for possible hepatoprotective effects. These plants are Carduus acanthoides and C. nutans (Asteraceae), Cichorium intybus (Asteraceae), Fumaria asepalae and F. vailantii (Fumariaceae), Gentiana olivieri (Gentianaceae) and Plantago lanceolata (Plantaginaceae). Stems, bracts and receptaculum of Cynara scolymus were used as natural reference drugs. Effects of the ethanolic extracts were studied using the carbon tetrachloride-induced hepatotoxicity model in rats. The extracts of F. vailantii and G. olivieri significantly prevented the elevation of plasma and hepatic malondialdehyde formation (evidence of lipid peroxidation) as well as enzyme levels (AST and ALT) in acute liver injury, which might be ascribed to their potent hepatoprotective activity. Liver sections were also studied histopathologically to confirm the biochemical results. (C) 2000 Elsevier Science Ireland Ltd. All rights reserved.