Reflecting the successful control of highly virulent and lethal infectious diseases achieved in recent years and also the serious side effects reported sometimes after vaccination even in relatively mild diseases vaccination is now being practiced on an individual base rather than compulsive base for groups. This urges strongly a re-inspection of all clinical entities from the standpoint of clinical preventive medicine. The rapidly developing high aging society we are facing also requests the systematization of clinical preventive medicine to maintain a healthy life as long as possible. In this symposium the health care information such as in radiation exposure in which the cause is clear and easy to be well documented is compared to that in ordinary industrial hazards which have complicated causes in general. As an example of clinical entities to be re-checked from the angle of clinical preventive medicine viral hepatitis is chosen and discussion is followed by prevention of cancer which is now the cause of highest mortality in Japan. In addition, adult health care system such as extensive health examinations is compared with the system of health care for children. Such an approach is expected to contribute to the systematization of clinical preventive medicine which is centered on the individual and not mass prevention in practice.