The present study determined the possible protective effect of pumpkin seed oil (PSO) on cellular apoptosis detection by immunehistochemical method (with (active) caspase-3, -4, 8 and -9 antibodies) in liver tissue and some biochemical parameters; serum ALT activity, vitamin E, plasma 8-OHdG and liver MDA levels, SDH and GPx activities on chronic liver injury induced by carbon tetrachloride (CCl4) in rats. A total of 80 Wistar rats were divided into eight groups of ten rats each: Group I served as control, receiving vehicle 0.9% NaCl (1.0 mL/kg); Group II was given intraperitoneally CCl4 at a dose of 0.2 mL/kg, 1:1 mixture with corn oil, twice a week for 8 weeks. Groups III, IV and V were daily treated with PSO through gavage for 8 weeks (1, 2 and 3 mL/kg, respectively). Groups VI, VII and VIII were administered with intraperitoneally CCl4 (0.2 mL/kg) twice a week and simultaneously PSO by gavage for 8 weeks (1, 2 and 3 mL/kg, respectively). Groups VII and VIII were showed a partial decrease of steatosis in the hepatocytes while the findings in the Group VI were similar to Group II. Compared to Group II, the severity of caspase-3, -8 and -9 activities were not changed in the Group VI but Group VII and VIII were partially reduced. As a result, although no positive effect of 1 mL/kg PSO on liver damage was observed, it has been concluded that PSO has some ameliorative effects by decreasing the levels of biochemical parameters and histopathology in 2 and 3 mL/kg PSO groups. Dose and duration dependent further investigations need to be performed to understand the dose that produces the best result without any side effect.