The use of nanosized materials is rapidly increasing, both in technological applications for daily use and in biomedical research. The use of these materials, especially for biomedical purposes is however still limited as the potential toxicity of nanomaterials warrants a lot of caution. The generation of a lot of toxicological data concerning nanomaterials sometimes creates a negative perception on their use. However, not all nanomaterials are the same and our understanding of how toxicity exerts itself and ways of how to control it for various particles is increasing. This control also offers us the possibility to exploit nanoparticle toxicity in a targeted manner, by means of selective autophagy induction or leaching of metal ions as a novel anticancer therapy. This manuscript provides an overview of work done on these topics, important achievements and key issues that need to be resolved to mature this novel scientific discipline. (C) 2012 Elsevier Ltd. All rights reserved.