The rapid aging of society and the resulting increase in medical expenses are common concerns of developed countries today. This article analyzes recent trends in medical ecology in Japan and suggests some countermeasures. More people will complain about their subjective symptoms because there will be more elderly persons and the wide-spread use of consumerized medical devices will create anxieties for health. Less people will visit clinics because, first, technology will improve the accuracy of self-diagnosis; second, better over-the-counter drugs will encourage self-medication; third, more medical care personnel other than doctors will deliver simple medical services; and fourth, the government will reduce public medical care spending, especially on mild illnesses, for financial reasons. Less people will visit large hospitals because the progress in and commercialization of diagnostic and therapeutic technologies will allow clinics to deliver more of the advanced medical services thus far available only in hospitals. In view of constructing a sustainable society, we propose to develop high-quality, lightly armed health care technologies for providing low-cost and easy-to-access health care as a foundation for maintaining human dignity, and to promote public education for the judicious application of such technologies.