It is both ethically and legally necessary that patients (or their surrogate decision makers) give informed consent for medical treatment. This principle requires that they be told: (1) the diagnosis; (2) the nature and purpose of the suggested treatment; (3) the possible risks of the treatment; and (4) treatment alternatives, including doing nothing at all. Further, this information must be adequately disclosed, and the patient or surrogate must make the choices freely; must fully understand the information; and must have sufficient decision making capacity.

Health care professionals have a responsibility to offer and carefully explain all appropriate information relevant to the patient's treatment decisions. The patient has a responsibility to ask questions and request further explanations, if necessary. Together, they can discuss the benefits and burdens of treatments, and the patient can give informed consent. At times, health care providers may also act both legally and ethically based on presumed consent or implied consent.