This dissertation examines specific phenomena that illustrate a unique aspect of the role of patient activism in shaping the practice of medicine. Each chapter focuses on a specific example. The four examples are the rise of Morgellons disease, activism by sufferers of chronic Lyme disease, research subject activism, and the use of patients to market Paxil for social phobia. I use these examples to examine various shifts of power that have occurred in medicine over the last few decades. These shifts can be generally divided into two types: a shift in power from physicians to patients and an overlapping shift in power from professional medicine to various corporate entities. In the past thirty years, patients have taken more and more control over their own medical care. Over this same time period the pharmaceutical industry became a highly profitable business, increasing its economic and political power and research has become more commercialized. The older fee-for-service model of medical practice has been replaced with a corporate model and the influence of professional medical bodies has waned. Each of the shifts documented here has its own moral story, but together they also point to larger trends in medicine that have important moral consequences. In the conclusion I point to four different points of tension for ethics: a shift in the locus of moral expertise, the changing physician-patient relationship, ambiguity in the goals of medicine, and the role of bioethicists as watchdogs for patients.