Some ethical issues facing contemporary medicine cannot be fully understood without addressing medicine's internal morality. Medicine as a profession is characterized by certain moral goals and morally acceptable means for achieving those goals. The list of appropriate goals and means allows some medical actions to be classified as clear violations of the internal morality, and others as borderline or controversial cases. Replies are available for common objections, including the superfluity of internal morality for ethical analysis, the argument that internal morality is merely an apology for medicine's traditional power and authority, and the claim that there is no single, "core" internal morality. The value of addressing the internal morality of medicine may be illustrated by a detailed investigation of ethical issues posed by managed care. Managed care poses some fundamental challenges for medicine's internal morality, but also calls for thoughtful reflection and reconsideration of some traditionally held moral views on patient fidelity in particular.