Disclosure in clinical practice is aimed at promoting patient autonomy, usually culminating in patient choice (e.g., to consent to an operation or not, or between different medications). In medical ethics, there is an implicit background assumption that knowing more about (X) automatically translates to greater, or more genuine, autonomy with respect to one's choices involving (X). I challenge this assumption by arguing that in rare cases, withholding information can promote a patient's autonomy (understood as the capacity for rational choice in (...) alignment with one's values and goals). (shrink)