The hepatoprotective activity of Pinus massoniana bark extract (PMBE) against hydrogen peroxide (H2O2)-induced damage in normal human liver L-02 cells and carbon tetrachloride (CCl4)-induced acute hepatotoxicity in mice was investigated. The L-02 cells were pre-treated with PMBE for 24 hours prior to exposure to 0.5 mM H2O2 for 3 or 24 hours. The cell viability, level of malondialdehyde (MDA) and glutathione (GSH), and the catalase (CAT) activity were evaluated. For in vivo experiments, mice were divided into groups and PMBE administered orally, after which each group was assigned a further treatment. Histopathological examination, the serum levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), and GSH, the liver tissue levels of MDA and GSH, the activities of CAT and glutathione peroxidase (GSH-Px), were evaluated. PMBE treatment decreased the level of MDA and increased the cell viability, GSH content and CAT activity in H2O2 treated L-02 cells treated for 3 hours. PMBE obviously decreased serum ALT, AST, ALP, and liver tissue MDA, while increasing serum GSH, and liver tissue CAT and GSH-Px activities. In conclusion, PMBE treatment prevents H2O2 and CCl4-induced liver damage, and therefore could have a potential clinical usage.