A teaching-oriented multimedia database authoring system, MILES (Multimediales Informations- und Lehrsystem), has been in development since 1980 in our department. The hardware consists of a network of personal computers connected to digital and, until recently, audio/video storage devices. The system provides a database capable of handling all kinds of multimedia data and computer programs. User-friendly software provides input, editing, retrieval, and communication; the authoring system allows these components to be organized into structures of complex menus, combined with free database access. More than 12,000 components have been stored, including ~3,500 pictures. The paper reports on an extensive field test, in which the system has been applied as a common source for all kinds of materials used in teaching physiology to students of medicine. Results show that the "new media" are powerful instruments for improving teaching and learning. However, they should not be expected to provide the sole basis for education. Their application still faces many problems regarding concepts, efficiency, and acceptance by students and staff.