Medical students' concerns that their education is not preparing them to be the doctors they could be can be traced in part to inadequacies in the basic concepts of health and disease they are taught, which prevent them from learning how to most effectively meet the challenges and exigencies of patient care. The author proposes an alternative theoretical perspective on the biological foundations of medicine by describing two divergent models of health and disease. The first, reductive isolation, represents the dominant theoretical approach to health and disease in contemporary medical education and practice. It emphasizes quantification and measurement and aims to peer beneath variability, subjectivity, and the infinite variety of patients' experiences to something universally definable, measurable, and objective. The second model, ascendant interrelation, takes as its starting point a special and prototypical property of the living organism, metabolism, in which the organism has an identity that transcends the material of which it is made, and in which such characteristics as form, wholeness, self-generation, and integration dominate. Medicine and the teaching of medicine must use both these models; the tools of reductive isolation are necessary but must be applied with a view to the larger and more complex reality of the patient as addressed by ascendant interrelation. Alone, reductive isolation does not offer an adequate perspective on the health of the whole human being, just as the well-functioning of the eye cannot be adequately explained without reference to seeing. In short, patients are more than their diseases; complex factors in their lives must not be overlooked as contributors to their illnesses or keys to healing.(ABSTRACT TRUNCATED AT 250 WORDS)