AbsractBackground: F. hepatica infection is rare and mostly subclinical. Migration of juvenile forms of F. hepatica into the host's liver is accompanied by an inflammatory reaction followed by fibrosis and cirrhosis. Objective: The aim of this study was to evaluate oxidative status by using a novel automated method in patients with Fasciola hepatica. Methods: Twenty two patients with a diagnosis of F. hepatica and 26 healthy volunteers were enrolled in the study. Their Total antioxidant capacity status (TAC), total oxidant status (TOS) and catalase were measured in them and oxidative stress index (OSI) was calculated. These measurements were also taken for the control group and the values were compared. Results: Plasma levels of total TOS and OSI were significantly increased in patients as compared with healthy controls (P<0.001, P<0.001, P=0.001, P=0.008) respectively. In contrast, TAC level was significantly lower in patients as compared with controls (p<0.05). There was no significant difference between the catalase results of the two groups (p>0.05). Conclusion: Total oxidative status and OSI were increased and total antioxidative status capacity was decreased in patients with F. hepatica infeciton. A high oxidative stress occurs during F. hepatica infection, which may cause severe damage in both the liver.