AIM, To study the role of N-acetylcysteine （NAC） as a protective agent in rifampicin （RMP）-induced oxidative hepatic injury of young rats. METHODS： Hepatic injury was produced by giving 50mg/kg body weight/day of RMP for 3 wk. A dose of NAC （100mg/kg body weight/day） was given in combination with RMP intraperitoneally. Analysis of lipid peroxidation, thiol levels, cytochrome P4se, superoxide dismutase （SOD）, catalase, glutathione peroxidase, reductase and transferase were estimated in liver along with the body weight, liver weight and histological observations. RESULTS： RMP exposure resulted in no change in body and liver weight while antioxidative enzymes were altered but the non protein thiol （GSH） status was well preserved. Cytochrome P450 system and peroxidation of lipids were induced by RMP exposure. Partial protection was observed with NAC against RMP-induced changes in liver, which was evidenced from the prevention of increase in lipid peroxidation and the reduction in SOD and catalase enzyme levels. CONCLUSION. NAC protects young rats against RMP- induced oxidative hepatic injury.