The restrictions implied in the reductionist (mechanistic) method, still predominant even at the advanced levels of textbook medicine, have caused grate disproportionalities across all areas of medicine. This has given rise to severe problems in health care. For example, highly comprehensive knowledge has been accumulated on the smallest components of the organism, such as molecules and cells, whereas insufficient consideration is given to the integrative functions of the human organism as a biopsychosocial entity and its interactions with the natural and social environment, despite its major importance to human health. If those limitations and their critical consequences are to be overcome, modern medicine will have to be enlarged by the systemic approach. This will decisively depend on new methods of integrative information and knowledge processing and system-analytical diagnostics on the basis of modern information technologies. Health informatics, therefore, has to play a specific role in the development of a systemic approach and its introduction to medicine and health care. This is a new responsibility for which the health informatics expert must be effectively prepared in the course of education. An account is given of a concept for appropriate teaching of the underlying principles, including an integrative presentation of the human organism as an information-processing system and as source of information in permanent interaction with the natural and social environment. This concept provides for ways and means to devise new, reasonable diagnostic strategies and to build a properly tuned system of health-supporting, preventive, therapeutic and rehabilitative measures. Individual health must be supported, last but not least, by social and political action. The systemic approach quite obviously may as well provide a key for major cost containment in health care.