Is medical commerce a recent phenomenon? Does it distort the patient–physician relationship? Are investor-owned firms the main source of medical commercialism? I contend that medicine has generally been commerce in the United States, that medical commerce is a problem when it creates or worsens physicians' conflicts of interest, and that these conflicts thrive in nonprofit organizations as well as in investor-owned firms. I provide a historical sketch to show that physician entrepreneurialism, rather than commerce generally, is the main source of physicians' conflicts of interest.Thanks are due to Jerome P. Kassirer, Albert R. Jonsen, and Joseph Fins for helpful comments on a draft. The history and themes herein are further developed in a book I am now writing, titled Medical Profession, Market and State in France, the United States and Japan.