Studies of home and abroad on the influence of external sustances on the activity of blood superoxide dismutase(SOD)are reviewed in this article.Trinitrotoluene,pollen and ultraviolet ray are known to be factors that could increase SOD activity in blood,while hyperbaric oxygen, micro wave radiation and some heavy metals such as lead and manganese could decrease SOD activity in blood.The physiological significance of the change of SOD activity and several determination...