Acute pancreatitis (AP) is a localized inflammation of the pancreatic gland that often leads to local and systemic complications. Cinnamic acids have been identified as interesting compounds with antioxidant, anti-inflammatory and cytotoxic properties. A pre-clinical study using L-arginine induced AP in the rat model was attempted to evaluate the antioxidant effect of Cinnamic acid. The result confirmed that the AP condition was developed in response to the injection of L-arginine causing significant changes in different pancreatic enzymes; amylase and lipase in addition to the oxidative stress biomarkers. The treatment with Cinnamic acid caused a marked effect on these investigated parameters. The findings of the present study demonstrated that Cinnamic acid provided effective protection against AP induced by L-arginine in rats since this compound was able to ameliorate serum enzymes released from pancreas, enzymatic and non-enzymatic antioxidant defense system and to prevent the lipid peroxidation in these tissues. More detail study about Cinnamic acid treatment reversing or reducing acute pancreatitis is needed.