The authors discuss law and ethics when medical decisions are to be taken by patients who are unable in any valid sense to express their own wishes. The main problem in legal terms is to protect an individual's free will as far as possible and ensure that his or her wishes, if known, are respected. If a patient's independent wishes cannot be known, then we must at least ensure that nothing is imposed which is not in his interest. Legal measures, however, are far from adequate in resolving all the concrete problems that emerge. The field of ethics does bring some better adapted solutions, but none is laid down in law. One such approach, involving a multidisciplinary advisory group in a department of geriatrics, is discussed.