Free radicals are incriminated as being responsible for cellular lesions during irradiation, inflammatory phenomena, and the syndrome of ischemia followed by reperfusion. These 3 processes are of interest to plastic surgeons. It would be useful to protect the tissue from the free radicals during irradiation for breast cancer with a view to secondary reconstruction in tissue of unproved quality. Limiting the inflammatory phenomena in burned patients would also be helpful. The ischemic reperfusion syndrome occurs in flap surgery, in microsurgery and during all surgical procedures which involve clamping pedicles. Finally shock, which causes an ischemic reperfusion syndrome over the entire organism, also favors the formation of free radicals and it is interesting to consider the possibility of combating the free radicals in the shock accompanying extensive burns. Among the enzymes destined to fight these radicals, superoxide dismutase was the first to be discovered and is the best known, since it has been the subject of numerous animal experiments and many applications in humans. Currently it seems more efficient than other substances in combating ischemic type lesions.