KIE: A review is provided of (1) state legislation on living wills and advance directives and (2) state court decisions and legislation authorizing family members to make the decision to withhold or withdraw life-sustaining treatment from adult patients. Five aspects of the emerging legal standards are summarized: the type of patient eligible; the type of treatment that may be withdrawn or withheld; designation of which family members are empowered to exercise authority; measures intended to prevent abuse of the new power by family members; and provisions empowering physicians to decide. The author suggests that the most prudent course would be to direct health care providers to accept family decisions unless it appears that the family is acting out of ignorance or in bad faith, in which case the decision would be referred to a hospital ethicist or ethics committee and then--only if there were good grounds to suspect ignorance or bad faith--to judicial review.