In this essay, I propose that the field of composition/rhetoric can make important contributions to the understanding of ethics based on our critical perspective on language as interactional and rhetorical. The actual language of decision making with ethical dimensions has rarely been studied directly in the literature, a crucial gap our field can usefully fill. To illustrate this approach, I analyze the language of research recruitment in two biomedical and behavioral studies, arguing that different ethical frameworks--a principle-based ethics of rights and a context-based ethic of care--license different kinds of interaction and rhetorical persuasion. The findings identify and complicate certain concepts and assumptions within these ethical frameworks, with implications for the context of regulated research in the university. (Contains 9 notes.)