Physicians are fiduciaries because of their knowledge and their license. The physician has power over the patient by virtue of greater knowledge gained through training and experience. The physician must complete many years of professional training before being allowed to practice medicine. This training is available to only a small number of individuals in the population, and it consumes many societal resources. This contributes to the societal policy that physicians should not take advantage of patients by virtue of their superior knowledge. Even more important to this policy is the limitation of the right to practice medicine to persons with this professional training.

The medical license carries with it five rights: the right to diagnose illness, the right to treat that illness by medical means, the right to prescribe drugs, the right to supervise nonphysician practitioners in the provision of medical services, and the right to collect fees for medical services provided by oneself and others. Some of these rights are shared by other licensed medical care practitioners, but taken together they give the physician a unique monopoly position in medical care delivery. In return for these rights, particularly the unique right to prescribe drugs, society expects physicians to exercise concern for the interests of patients. If licensing and knowledge were the only sources of power in the physician–patient relationship, there would be no need to extend this fiduciary duty to physicians in need of medical care. In fact, the duty owed to physicians in need of medical care is only slightly less than that owed to laypeople because the law recognizes other factors that affect the bargaining power of the patient.