[Oxygen radicals: rescue or threat?]

In this review the chemistry and formation of oxygen radicals is surveyed. Various physiological protective mechanisms against oxygen radicals as well as the consequence of too much or too little oxygen radicals in diseases is discussed. In this respect attention is given to hypoxia/ischemia, bronchopulmonary dysplasia, retrolental fibroplasia, thalassaemia, Down's syndrome and chronic granulomatous disease. Finally some new developments in pharmacotherapeutic possibilities which might play a role in prevention or amelioration of free radical pathologies are mentioned.