Abstract
When patients are no longer able to participate effectively in decision making, an advance directive or living will may assist clinicians faced with choices about whether or not to prolong their lives. But living wills are an imperfect substitute for active patient participation. The opinion of an informed proxy could help to interpret what a patient's wishes might have been in the light of his or her present condition and its possible treatment. Practical suggestions are made about informal arrangements whereby general practitioners might help to make such an opinion available when needed.