There has been significant debate about whether the moral norms of medical practice arise from some feature or set of features internal to the discipline of medicine. In this article, I analyze Edmund Pellegrino’s conception of the internal morality of medicine, and situate it in the context of Alasdair MacIntyre’s influential account of “practice.” Building upon MacIntyre, Pellegrino argued that medicine is a social practice with its own unique goals—namely, the medical, human, and spiritual good of the patient—and that the (...) moral norms that govern medical practice are derived from these goals. After providing an overview of Pellegrino’s work, I discuss some forceful objections to his theory—specifically, that it is too rigid and incapable of entering into dialogue with contemporary values systems; that it is dependent on an external conception of human flourishing; and that it is incompatible with the rapidly changing nature of modern medicine. In the final section of this article, I consider how theorists working in the Hippocratic tradition might respond to these objections against ethical essentialism by drawing upon MacIntyre’s historico-cultural method as well as what he calls Aristotle’s “metaphysical biology.”. (shrink)