The apparent demographic changes in our society with a substantial increase of elderly people threatened by restrictions due to diseases, invalidity, and disability call for new forms of "active prevention," namely anti-aging medicine. This kind of medical intervention is not intended to stop or reverse the aging process, but to recognize and decrease the risks of developing chronic diseases provoked by genetic disposition, lifestyle, and biochemical changes and to initiate preventive strategies. These medical interventions are based on knowledge about biological organ functions during the course of a lifetime that proceed according to a general time frame: increase of function from birth to the age 15-28, followed by a continuous decrease until the "disability threshold" is reached, with decompensation of organic function, leading to disease and possibly to death. In light of this background, a modular system of prevention was generated for practical medicine, including risk calculators for detection of the individual health risk and diagnosis of premature loss of organic function using specific vitality tests. Finally, a concept of preventive methods was elaborated based on scientific and clinical evidence.