Auranofin, a disease-modifying gold compound, has been empirically applying to the management of rheumatoid arthritis. We investigated a protective effect of auranofin against hepatic injury induced by cocaine. Cocaine (75 mg/kg) markedly increased serum alanine amino transferase (ALT) (4,130 IU/l) and aspartate amino transferase (AST) (1,730 IU/l) activities at 16 hr after treatment, and induced hepatic necrosis surrounding central veins in mice. Concurrently, overexpression of heme oxygenase-1 (HO-1), a rate-limiting enzyme for heme degradation and an oxidative stress marker, was identified at the edges of cocaine-mediated necrotic area. Auranofin (10 mg/ml, i.p.) significantly induced hepatic HO-1 protein in mice from 12 hr after treatment. Interestingly, pretreatment with auranofin resulted in the prevention of the increase of serum ALT and AST activities in a dose-dependent manner. On the other hand, although cocaine increased tumor necrosis factor α (TNFα) gene expression in mouse livers, cocaine-induced liver injury was observed in TNFα deficient mice as well as wild-type mice. Auranofin-inducted HO-1 gene expression was observed in human primary hepatocytes as well as mouse primary hepatocytes. The present findings suggest that auranofin is effective in preventing cocaine-induced hepatic injury, and HO-1 may contribute to protect against chemically-induced cytotoxicity.