Informed consent to medical procedures tends to be construed in terms of principle-based ethics and one or other form of expected utility theory. These constructions leave problems created by imperfect communication; subjective distress and other emotions; imperfect knowledge and incomplete understanding; complexity, and previous experience or the lack of it. There is evidence that people giving consent to therapy or to research participation act intuitively and assess consequences holistically, being influenced more by the magnitude of outcomes than their probability. People (...) avoid decisions they may regret, but modern regret theory has received little attention in discussions of informed consent. This essay suggests ways in which regret may be acknowledged in the consent process and in the assessment of the information that is an intrinsic part of it. (shrink)