This is a comprehensive medical and scientific dictionary for the 21st century. New vocabulary is constantly being introduced into fast moving medico-scientific disciplines such as genomics clinical trials medico-legal health economics and pharmacovigilance. This new terminology is included in this dictionary clearly defined and accurately translated into Spanish. The dictionary contains more than 28 000 main entries and many subentries: (a) medical terms used outside the medical community including colloquial usage; (b) technical medical terms in current use in clinical practice and research; (c) new technical terms in the fields of medicine medical research and basic scientific research applied to medicine defined in recent years. The breadth of subjects covered and the accessibility of the definitions make it user-friendly for the educated general public while the level of detail and state-of-the-art coverage of recent terminology make it a unique tool for professionals.