This paper addresses the problem of ‘premature consent’. The term ‘premature consent’ denotes patient decisions that are: formulated prior to discussion with the appropriate healthcare professional ; based on information from unreliable sources ; and resolutely maintained despite the HCP having provided alternative reliable information. HCPs are not obliged to respect premature consent patients’ demands for unindicated treatments. But why? What is it that premature consent patients do or get wrong? Davis has argued that premature consent patients are incompetent and (...) misinformed. We argue that this view is not sustainable. A more plausible position asserts that premature consent threatens the integrity of the medical profession. We argue that this gives rise to a negative patient duty which premature consent patients fail to honour. We argue for a further positive duty of good faith engagement in shared decision-making. This implies willingness to potentially revise or justify one’s evaluative bases. Fundamentally, the problem with premature consent patients is that certain of their evaluative bases are not open to revision. They therefore fail in their duty to participate faithfully in the shared decision-making process. (shrink)