Nanomedicine is the sub-discipline of nanotechnology striving to use this technology to improve existing therapeutics or create new ones. By taking advantage of the development of chemistry, physics, materials science, engineering and biotechnology, the interdisciplinary integration of nanotechnology promotes the research and commodification of medicine and brings significant change in medication. In other words, Nanotechnologies are the extensions of existing therapies and products that are already regulated: drugs, devices, and biologics, as well as combination products. Because this raises the pressing question of whether existing oversight frameworks and regulatory approaches are adequate and appropriate for nanomedicine, this article explored the regulations in U.S. and Taiwan to review the derived problems of nanodrugs. Further, due to lack of fundamental research of nanotoxicology and mature detecting and analyzing technique, nanomaterials are criticized to pose a great potential of risk of harm for human with a high degree of uncertainty. In such status of “non liquet,” this article tried to exploring the so called “safety” of drugs by comparing the concepts of safety in premarket approval of drugs, the design defect in product liability in U.S. and the implied concept in Drug Hazard Relief Act in Taiwan, to seek a balance for the safety of patients and new drug development in Taiwan.