Silymarin is a plant-derived flavonoid from the plant Silybum marianum. The main component of the silymarin complex is silybin, which is a mixture of two diastereomers A and B in approximately 1:1 proportion. The drug possess hepatoprotective and antioxidant activity. The hepatoprotective effect is due to stimulation of synthesis of structural and functional proteins and phospholipids, as well as acceleration of the regeneration of hepatocytes. Antioxidant effect is determined by interaction of bioflavones with free radicals in the liver and its detoxication. In such manner the process of peroxidation of the lipids is interrupted and further liver destruction is prevented.