Informed consent has emerged as an issue both of great importance and substantial uncertainty and confusion. This paper examines some of the conceptual and practical complexities of informed consent and suggests some impli cations of our empirical knowledge about consent. Among the issues considered are the purposes of informed consent, ethical versus legal functions of informed consent, the dis tinction between informed consent and consent forms, and whether informed consent is an ideal that can never be achieved. It is argued that informed consent is presently not a reliable method of protecting subjects and patients from harm because of limited commitment of professionals to the concept of informed consent, the tendency for procedures to be substituted for substance, the dependence of the quality of consent on many factors, including the characteristics of the subjects or patients, and the tendency of human subjects review committees to confine their attention to consent forms rather than to the process by which consent is sought.