PURPOSE: To investigate the potential protective effect of allopurinol on reperfusion injury by determining the inflammatory response through the measurement of tumor necrosis factor-alpha (TNF-alpha). METHODS: Sixty rats were distributed into two groups: control and allopurinol and each group was divided into three subgroups, ischemia for two hours, ischemia for three hours and ischemia simulation. Allopurinol group rats received 100mg/kg dose of allopurinol, whereas control group rats received an equivalent dose of saline. Clamping of the infrarenal aorta was performed for two or three hours depending on the subgroup. Ischemia simulation subgroups did not suffer ischemia, just aortic dissection, and maintenance for three hours. After 72 hours of reperfusion, blood was collected by cardiac puncture for TNF-alpha measurement. RESULTS: Allopurinol reduced TNF-alpha significantly (p <0.001) when compared to the matching control subgroups (control X allopurinol in ischemia for two hours and for three hours). CONCLUSION: Allopurinol reduced the concentrations of serum TNF-alpha when used at different times of ischemia followed by reperfusion, which might indicate reduction of the inflammation provoked by the reperfusion injury.