Over the last half-century and more, as responsibility for decisions about medical care shifted from physicians to patients, “informed consent” emerged as a central ethical principle. Agreement to treatment, under this principle, is predicated on a free choice made by a competent patient. Being “informed” means not only that the risks and benefits of treatment have been fully explained but also that the patient fully understands them. While competence has been a key focus, the issue of understanding is also important: can patients unaware of their real situation make free and informed decisions?