As the science and technology of nanomedicine speed ahead, ethics, policy and the law are struggling to keep up. It is important to proactively address the ethical, social and regulatory aspects of nanomedicine in order to minimize its adverse impacts on the environment and public health and also to avoid a public backlash. At present, the most significant concerns involve risk assessment, risk management of engineered nanomaterials and risk communication. Although in vivo animal experiments and ex vivo laboratory analyses can increase our understanding of the interaction of engineered nanomaterials in biological systems, they cannot eliminate all of the uncertainty surrounding the exposure of a human subject to nanomedicine products in clinical trials. Significant risks can still materialize after a product has cleared the Phase I hurdle and is in Phase II or III clinical trials. Furthermore, as the use of engineered nanomaterials in nanomedicine increases, questions of social justice, access to healthcare and the use of nanotechnology for physical enhancement become increasingly important.