Formaldehyde (methanol) is a chemical substance, with nasty smelling which is normally used to fix cadavers and histological process. The main use of formaldehyde is in production of synthetic resins, wood-plastic products and fiber industry. Formaldehyde has a negative impact on performance of organ system with oxidative stress in the body. specially on the hepatic. Some studies have demonstrated that antioxidants such as vitamin C can play an important role to protect from damage caused by harmful substance. The aim of this study was to evaluate the protective effect of vitamin C on hepatic damage caused by formaldehyde in rats. This study included 24 adult male rats with weighing 250-300 gr. rats were randomly divided into 3 groups each comprising 8 rats. 1-Control group: exposed to normal saline (1cc/kg per day for 10 days) that injected intraperitoneally, 2-groups E1: exposed to formaldehyde 10mg/kg per day for 10 days, 3-group E2: simultaneously exposed to vitamin C (200mg/kg) per day for 10 days& formaldehyde 10 mg/kg intraperitoneally 10 days. At the end of the exposure period, the mice were placed under anesthesia and surgery. The blood samples were taken for isolation of serum and measurement of AST and ALT in. In this study, AST and ALT levels of 24 adult rats in the all groups were measured and the results were compared. The amount of AST in the all groups was significant (P< 0.05). The amount of AST in group E2 compared to controls was significant (P= 0< 0.05) and the amount of AST in group E2 compared to E1 was not significant (P= P> 0.05). Also, comparison of the results showed significant difference in serum ALT in third group. Serum ALT level in E1 compared to control group was significant (P< 0.05) and ALT in group E2 compared to control group was significant (P< 0.05). The amount of ALT in group E2 compared to E1 was not significant (P= 0.847). According to this study, intraperitoneal administration of formaldehyde at a dose of 10 mgr/kg per 10-day can increase AST and ALT and vitamin C at a dose of 200 (mg/kg) per day for 10-days can reduce amount of AST and ALT in adult rats exposed to formaldehyde