The present invention provides a method for preventing, alleviating or treating a liver disease, comprising administering a composition comprising a Triticum aestivum Lamarck leaf extract or a fraction thereof to a subject in need thereof. Therefore, the method for preventing, alleviating or treating a liver disease of the present invention can improve the morphological change of liver tissue due to liver injury, inhibit apoptosis of hepatocytes, increase the synthesis of antioxidant enzymes such as glutathione (GSH) and superoxide dismutase (SOD) which can reduce oxidative stress in liver tissue, and reduce the levels of glutamic oxaloacetic transaminase (GOT) and glutamic pyruvic transaminase (GPT) which are known to change sensitively in liver diseases.