CONTEXT: The principal bioactive lignan of Schisandra chinensis fructus, commonly used for traditional Chinese medicine, is schisandrin A. Schisandrin A has been widely reported as being very effective for the treatment of liver disease. However, the mechanisms of its protective effects in liver remain unclear. OBJECTIVE: To explore the hepatoprotective mechanisms of schisandrin A. MATERIALS AND METHODS: d-Galactosamine (d-GalN)-induced liver injury in mice was used as a model. Schisandrin A was examined for its protective mechanisms using hematoxylin-eosin (HE) staining, enzyme-linked immunosorbent assay (ELISA), western blotting and real-time PCR (RT-PCR). RESULTS: Aspartate amino-transferase (AST) and alanine transaminase (ALT) levels in the schisandrin A group were significantly decreased (p?