During the last years, special emphasis was directed towards the relation between the molecular and cellular alterations produced by free oxygen radicals and the normal and pathologic implications of nitric oxide. Moreover, lately it is believed that a true radical cascade might exist between the reactive species of oxygen and nitrogen during stress of various causes. In this way, their succession would produce a temporal prolongation of the complex cellular alterations produced by stressing aggressions. In the present paper, we were interested in presented some selective aspects regarding the interactions between oxidative and nitrosative stress in the modulation of the nociceptive behavior in rats. We report here a significant correlation between the results of the hot-plate latency time and the values of some oxidative and nitrosative stress markers.