In evidence-based medicine (EBM), methodology has become the central means of determining the quality of the evidence base. The “gold standard” method, the randomised, controlled trial (RCT), imbues medical research with an ethos of disinterestedness; yet, as this essay argues, the RCT is itself a rhetorically interested construct essential to medical-professional boundary work. Using the example of debates about methodology in EBM-oriented research on complementary and alternative medicine (CAM), practices not easily tested by RCTs, I frame the problem of method (...) as a fundamentally rhetorical problem, situated within a boundary drama, and deeply rooted in the discursive practices of science and medicine. The genre of the RCT report, for example, idealises the research process and can tilt the course of arguments about CAM, while the notion of efficacy can function as a rhetorically mobile boundary object that can redefine the very terms of debate. I suggest herein that arguments about method in CAM debates can productively be read, metonymically, as expressions of more general anxieties in medicine about knowledge and evidence, community values, and professional boundaries; as such, these debates can illuminate some of the rhetorical dimensions of EBM. (shrink)