AIM: To investigate the protective effect of medical ozone (O3) combined with Traditional Chinese Medicine (TCM) Yigan Fuzheng Paidu Capsules (YC) against carbon tetrachloride (CCl4)-induced hepatic injury in dogs.METHODS: Thirty healthy dogs were divided randomly into five groups (n = 6 in each group), namely control,oleanolic acid tablet (OAT), O3, YC and O3 + YC, given either no particular pre-treatment, oral OAT, medical ozone rectal insulfflation every other day, oral YC, or oral YC plus medical ozone rectal insulfflation every other day, respectively, for 30 consecutive days. After pre-treatment, acute hepatic injury was induced in all dogs with a single-dose intraperitoneal injection of CCl4.General condition and survival time were recorded.The biochemical and hematological indexes of alanine aminotransferase (ALT), aspartate aminotransferase/alanine aminotransferase (AST/ALT), serum total bilirubin (TBIL), prothrombin time (PT), blood ammonia (AMMO),and blood urea nitrogen (BUN) were measured after CCl4 injection. Hepatic pathological changes were also observed.RESULTS: Compared to the other four groups, the changes of group O3 + YC dogs' general conditions(motoricity, mental state, eating, urination and defecation) could be better controlled. In group O3 +YC the survival rates were higher (P ＜ 0.05 vs group control). AST/ALT values were kept within a normal level in group O3 + YC. Hepatic histopathology showed that hepatic injury in group O3 + YC was less serious than those in the other four groups.CONCLUSION: Medical ozone combined with TCM YC could exert a protective effect on acute liver injury induced by CCl4.