This paper throws some light on the nature of argumentation, its use and advantages, within the setting of doctor–patient interaction. It claims that argumentation can be used by doctors to offer patients reasons that work as ontological conditions for enhancing the decision making process, as well as to preserve the institutional nature of their relationship with patients. In support of these claims, selected arguments from real-life interactions are presented in the second part of the paper, and analysed by means of (...) a model of argumentation borrowed from classical rhetoric, and refined according to the modern orientation of the pragma-dialectic approach. (shrink)