Bachground: One of the major role of liver is metabolism of xenobiotics and detoxification. But sometimes, during metabolism of xenobiotics produce active and more toxic agents which cause liver damege and disease. Use of nature products from vegetables in the treatment of diseases and liver diseases has a long history, especially in Eastern medicine. Materials and Methods: In this study, we have investigate the protective effects of polyphenolic extracts of Silybum marianum and Cichorium intybus. Liver damage induced with hepatotoxin, thioacethamide. Extracts was injected every day for a duration of 3 days, to rats, at a dosis of 25 mg/kg body weight together with thioacetamide at a dosis of 50 mg/kg body weight. In order to investigation the hepatoprotective effect of extracts against thioacetamide, activities of serum aminotrasferases (SGOT and SGPT), alkalin phosphatase, bilirubin, Na+ and K+ were measured. Results: Activities of serum aminotrasferases (SGOT and SGPT), alkalin phosphatase and bilirubin were decreased significantly in rats treatmented with extracts in compared to thioacetamide group. Conclusion: The results showed potent protective effects of these extracts against the thioacetamide induced hepatotoxicity that are due to antioxidant effet of polyphenolic compound.