Nanosized particles (NPs) have recently been proposed for extensive use, including into the biomedical field. As a result, research on toxicity and oxidative stress concerning the interaction of nanoparticle and the living organism has attracted increasing interest among specialists. Two different targets have been the motor of this type of research: 1) the safety concern regarding such NPs large-scale use along with the need to generate antidote solutions to possible adverse effects, 2) the idea of influencing oxidative damage and of using them for elaborating anticancer/antimicrobial therapies. Present study reviews recent research achievements within the proposed theme taking into account the nature and particularities of each type of nanoparticle.