In this study, the hepatoprotective activity of ethanol extracts of Fumaria vaillantii Lois. was investigated against CCl4-induced toxicity in rats. F.vaillantii (500mg/kg) caused a significant decrease in the plasma aspartate aminotransferase (AST), alanine aminotransaminase (ALT) and tissue malondialdehyde levels, and a significant increase in the reduced glutathione and catalase levels, compared with the CCl4 group. These findings were approved by histopathological observations. Additionally, a significant decrease was found in liver Cu levels (18.5%) of the extract-treated group (500mg/kg), while an increase in liver Zn (16.2%) levels was observed compared with the CCl4 group. These changes in liver Zn and Cu levels caused by F.vaillantii extract may contribute to its positive effects on liver toxicity. Phenolic acids and flavonoids in the extract were examined and the extract was standardized by reversed-phase high-performance liquid chromatography with diode array detection on the basis of rutin, chlorogenic and caffeic acids as markers.