The prominence of physicians in highly interdependent medical systems
confers tremendous power on them, individually and as a profession. Wi
th this power comes an ethical responsibility to be deeply concerned a
bout medical systems. Examples of medical systems include the process
of treating patients with diabetes; a hospital; the development and te
sting of new medical procedures; and a medical practice, including loc
ations of care, billing, and collection of fees for medical care. The
physician who is willing to learn about the nature of systems,how to c
ontrol them, and how to improve them can significantly influence medic
al systems. Many persons in health care organizations identify strongl
y with their individual profession or department. Management structure
s, professional organizations, and methods of billing for services rei
nforce these divisions. This fragmented environment allows the structu
re of medical systems to evolve piecemeal from the various actions and
points of view of physicians, nurses, administrators, patients, and p
ayers. Improvement results from new structures that are purposefully d
esigned. To achieve improvement, people must look beyond their own pro
fessional or organizational identities and see themselves as part of t
he larger system. Even a rudimentary understanding of the structures a
nd dynamics of systems combined with clinical knowledge can equip a ph
ysician to collaborate with colleagues to diagnose faults of a system
and design remedies. This paper explores the nature of medical systems
and develops ideas their proper application to medicine and the activ
ities of physicians.