This essay explores the role of informal logic and its application in the context of current debates regarding evidence-based medicine. This aim is achieved through a discussion of the goals and objectives of evidence-based medicine and a review of the criticisms raised against evidence-based medicine. The contributions to informal logic by Stephen Toulmin and Douglas Walton are explicated and their relevance for evidence-based medicine is discussed in relation to a common clinical scenario: hypertension management. This essay concludes with a discussion on the relationship between clinical reasoning, rationality, and evidence. It is argued that informal logic has the virtue of bringing explicitness to the role of evidence in clinical reasoning, and brings sensitivity to understanding the role of dialogical context in the need for evidence in clinical decision making.