The aim of this lecture is to illustrate how argumentation theory can be used as a descriptive and evaluative tool to analyze the content of direct-to-consumer health advertising (DTCA). By illustrating the strategies of argumentation applied in specific adverts, it will be shown how these adverts can shift between rational and unreasonable forms of discourse that have important implication at the public health level. More specifically, on the one hand, this lecture will be based on the use of analytical tools from the pragma-dialectic theory of argumentation to highlight the claims made in these adverts and the explicit and implicit premises that support those claims. On the other hand, by relying on the concepts of “argument-scheme” and “fallacy”, the arguments found in the adverts will be evaluated to identify dialectical (reasonable) versus rhetorical (persuasive) argumentative moves. Findings from the analysis will be discussed in light of current discussions on patient and consumer autonomy in decision-making, on health literacy and empowerment.