Abstract: OBJECTIVE To investigate therapeutic effects and mechanisms of low dose broncholysin on CCl₄ induced chronic hepatic injury in rats. METHODS Rats were divided into control group, model group, low dose NAC low, middle and high dose group, and positive control group. Rats in low dose NAC low, middle and high dose group were given NAC 45, 90, 180 mg·kg^-1 respectively. Rats in positive control group were given atomolan 54 mg·kg^-1. Rats in control group and model group were given sterilized normal saline. A chronic hepatic injury model was induced via intraperitoneal injection of CCl₄. 24 h after the last administration, the levels of ALT, AST in serum and SOD, MDA, GSH and Hyp in hepatic tissue content were detected. Liver histopathological changes were observed. Immunohistochemistry was used to detect the expression of Nrf2 and HO-1 in hepatic tissue. RESULTS Compared with rats in the model group, the levels of ALT, AST, MDA and Hyp raised(P<0.01), levels of GSH and SOD decreased, protein express of Nrf2 and HO-1 raised, but there were no statistically significant. Compared with rats in the control group, ALT, AST in serum of three NAC groups all decreased(P<0.01), SOD, GSH and Hyp in low and medium dose groups, GSH, Hyp in high dose group had statistically significant(P<0.01 or P<0.05), MDA in the three NAC groups decreased, but there were no significant. Nrf2 and HO-1 were increased in the three NAC groups, and the low dose groups there was statistically significant. CONCLUSION Low dose broncholysin play an important role in preventing chronic hepatic injury of the rats. Low dose broncholysin treatment may help to against oxidative stress by regulating the expression of Nrf2 and HO-1.