Medical ethics could be better understood if some basic theoretical aspects of practices in health care are analysed. By discussing the underlying ethical principles that govern medical practice, the student should also become familiar with the notion that medical ethics is much more than the external application of socially accepted moral standards. Professions in general and medicine in particular have internal values that command their moral virtuosity at the same time as their technical excellence. Three examples where clinical practice can (...) be clearly shown to require an ethical analysis are given: medical praxiology illustrates the motives, means and aims of physicians and patients; clinical decision-making as a practical syllogism that reaches prescriptive conclusions based on medical knowledge and the patient's wishes/intentions. Finally, diagnostics as an ethical bayesian approach is discussed, where the patient informedly decides the benefits and risks of further testing. (shrink)