We aimed to identify the hepatoprotective effects of Terminalia chebula water extract (TCW) and its corresponding pharmacological actions using C57/BL6 mice model of tert-butylhydroperoxide-(t-BHP-) induced acute liver injury. Mice were orally administered with TCW (0, 50, 100, or 200 mg/kg) or gallic acid (100 mg/kg) for 5 days before t-BHP (2.5 mM/kg) injection. Liver enzymes, histopathology, oxidative stress parameters, antioxidant components, and inflammatory cytokines were examined 18 h after t-BHP injection. t-BHP injection caused dramatic elevation of serum AST, ALT, and LDH level, while TCW pretreatment notably attenuated these elevations. Inflammatory cytokines including TNF-α, IL-1β, and IL-6 were notably increased in hepatic tissues, and then these were efficiently attenuated by TCW pretreatment. t-BHP injection notably increased malondialdehyde, total reactive oxygen species, and nitric oxide in the liver tissue, while it markedly dropped the antioxidant activities including total antioxidant capacity, total glutathione contents, glutathione peroxidase, superoxide dismutase, and catalase. TCW pretreatment remarkably ameliorated these alterations, and these effects were relevant to gene expressions. Histopathological examinations supported the above findings. Collectively, these findings well prove that TCW beneficially prevents acute and severe liver injury and clarify its corresponding mechanisms involved in the inhibition of oxidative stress and inflammatory cytokines.