Silymarin is a traditional hepatoprotective herb for the adjuvant therapy of liver diseases,which shows marked pharmacological activities such as antioxidant and anti- inflammatory properties. This paper introduces the action mechanism of silymarin in regulating liver function,ameliorating hepatic fibrosis,protecting pancreatic cells,suppressing the growth of tumor cells,and inhibiting the replication of hepatitis C virus. Silymarin is considered to be a natural medicine with little toxic or side effect at a high dose. It holds promise for anti-tumor,antioxidant,anti- inflammatory,and antiviral application.