In the last years, increasing biological interest is emerging for nanotechnology that can improve pharmacological treatments, by using nanomaterials. In particular, cerium oxide nanoparticles, considered one of the most interesting nanomaterials for their catalytic properties, show a promise for application in therapy. Due to the presence of oxygen vacancies on its surface and autoregenerative cycle of its two oxidation states, Ce3+ and Ce4+, nanoceria can be used as an antioxidant agent. Because many disorders are associated with oxidative stress and inflammation, cerium oxide nanoparticles may be a tool for the treatment of these pathologies. In this review we analyze the opinions, sometimes conflicting, of the scientific community about nanoceria, together with its capability to protect from various damages that induce cells to death, and to reduce oxidative stress, associated with a consequent reduction of inflammation.