Acute inflammatory response is the body’s direct response to noxious stimuli or to tissue necrosis. Ischemia-reperfusion lesion is a clinical state of acute inflammation with leucocyte-induced tissue damage. Ischemia promotes an inflammatory response which sensitizes tissues to further damage during reperfusion. Reperfusion activates inflammatory mediators from remote vascular or tissue sites or from the local vascular bed. Reperfusion remains the cornerstone for the repair of ischemic areas. Recently it is emphasized that repeated ischemic episodes of small duration with reperfusion interval periods in between make tissues more resistant to further long-termed ischemia. This is the I.P phenomenon. Many pharmacological agents (such as volatile anesthetics) are capable of inducing I.P. Other measures that can prevent or reduce ischemia-reperfusion injury, are controlled reperfusion, antioxidant, anti-complement and anti-leucocyte therapy.