Biological radicals resulted from oxidative stress has been implicated in human diseases, such as cancer and aging. There is, however, a paucity of reliable methods for in vivo or ex vivo detection of either radical formation, the end-products of radical formation or susceptibility for radical formation. The Rabbit polyclonal anti-DMPO can be used to detect the stable nitrone end-product of protein and DNA radicals in ELISA assays, blot analyses and confocal microscopy. This rabbit polyclonal anti-DMPO antiserum will replace a previously licensed one which is no longer available (E-186-2003). The availability of anti-DMPO from three different sources will greatly expand the ability of researchers to use anti-DMPO in conjunction with other antibodies.