After distinguishing two different meanings of the notion of a 'morality internal to medicine' and considering a hypothetical case of a society that relied on its surgeons to 'eunuchize' priest/cantors to permit them to play an important religious/cultural role, this paper examines three reasons why morality cannot be derived from reflection on the ends of the practice of medicine: (1) there exist many medical roles and these have different ends or purposes, (2) even within any given medical role, there exists multiple, sometimes conflicting ends, and, most critically, (3) the ends of any practice such as medicine must come from outside the practice, that is, from the basic ends or purposes of human living. The paper concludes by considering whether these ends external to medicine are universally part of the moral reality or whether they are socially constructed. The paper argues that, even if various cultural accounts of the common, universal morality are 'socially constructed,' they may, nevertheless, be reflections, however, imperfect, of a more universal common morality that should be thought of as real. Therefore, the morality of medicine must come from a more fundamental morality external to medicine. That external morality will be socially constructed, but may nevertheless reflect an underlying common morality.