Ischemia denotes deficiency in blood supply to tissues due to obstruction of the arterial blood flow. Tissue injury and death occur as a result of the initial ischemic insult, which is determined primarily by the magnitude and duration of the interruption in the blood supply, and then subsequent damage induced by reperfusion. Ischemia-Reperfusion injury (IRI) is defined as the cellular dysfunction and death, following restoration of blood flow to previously ischemic tissues. Reestablishment of blood flow is essential to salvage ischemic tissues. However reperfusion itself paradoxically causes further damage, threatening function and viability of the organ. IRI occurs in a wide range of organs including the heart, lung, kidney, gut, skeletal muscle and brain and may involve not only the ischemic organ itself but may also induce systemic damage to distant organs, potentially leading to multi-system organ failure.