The notion of a rhetoric of science argues that scientific writing is not unproblematically neutral and objective, but rather laden with both theory and value and necessarily persuasive. The nature of persuasion within the profession of medicine is studied here through an analysis of rhetorical strategies at work in medical journal articles. (All articles are on the subject of functional headache and appear after 1982 in such journals as the Journal of the American Medical Association, The Lancet, The New England Journal of Medicine and Headache.) The analysis is organized using the Aristotelian categories of invention (the discovery or creation of arguments), arrangement (their organization in the most persuasive order) and style (including such matters as the use of the passive voice and the avoidance of figurative language). The result of the analysis is a comprehensive inventory of strategies medical authors use in order to influence their peers. The inventory provides a vocabulary and a procedure for analysis of medical rhetoric in general; that is, it goes some way to enabling a medical metadiscourse. The analysis further suggests that rhetorical studies, as a discipline, has much to contribute to medicine's project of examining its own assumptions and scrutinizing its own dominant paradigm. Identifying rhetorical strategies at work in medical journals is one way to articulate medical values and to understand them as instruments of action within the profession.