Ischaemia-reperfusion injury is a complex phenomenon often encountered in surgical practice. The consequences of such injury are local and remote tissue destruction, and sometimes death. Several different processes have been implicated. This review discusses the pathology of such injury, the mechanisms of free radical production, and the role of neutrophils and endothelial factors in ischaemia-reperfusion. Finally, several mechanisms that limit ischaemia-reperfusion injury are discussed and a number of novel therapies presented.