Merck Manual

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Informed Consent


Charles Sabatino

, JD, American Bar Association

Reviewed/Revised May 2021 | Modified Sep 2022
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Consent of the patient is a prerequisite for any medical intervention. However, that consent often does not need to be explicit. For emergency care, consent is normally presumed, referred to as the doctrine of presumed consent. For interventions considered routine and unlikely to cause harm (eg, routine phlebotomy, placement of an IV line), circumstances are typically considered to imply consent. For example, by holding out their arm, patients are presumed to indicate consent to receive certain routine interventions. For more invasive or risky interventions, express informed consent is always required.

To give informed consent, patients must have legal and clinical capacity Capacity (Competence) and Incapacity Historically, “incapacity” was considered primarily a clinical finding, and “incompetency” was considered a legal finding. That distinction, at least in terminology, is no longer firmly recognized... read more . Health care practitioners obtaining informed consent must be qualified to explain the risks and benefits of the intervention and to answer appropriate questions. The law requires that health care practitioners take reasonable steps to communicate adequately with patients who do not speak English or who have other communication barriers.

Ethical and legal authorities generally agree that health care practitioners are obligated to ensure, at a minimum, that patients understand

  • Their current medical status, including its likely course if no treatment is pursued

  • Potentially helpful treatments, including a description and explanation of potential risks, benefits, and burdens

  • Usually, the practitioner’s professional opinion as to the best alternative

  • Uncertainties associated with each of these elements

Practitioners should be clear about the prospects of recovery with treatment and, if treatment is successful, what life will be like afterward. Generally, these discussions are noted in the medical record, and a document describing the discussion is signed by the patient.

Although practitioners are ethically bound to provide sufficient information and to encourage decisions judged to be in the patient’s best interest, patients have the right to refuse treatment. A patient’s refusal of treatment is not considered to be attempted suicide or evidence by itself of diminished capacity, nor is the health care practitioner's compliance with the patient’s refusal legally considered physician-assisted suicide. Rather, the subsequent death is considered legally to be a natural consequence of the disease process itself.

A refusal of care, if puzzling, should prompt the health care practitioner to initiate further discussion. If the patient's legal capacity seems questionable, such capacity should be assessed, but assessment should not be sought solely because the patient is refusing treatment. If refusal of treatment will hurt other people, such as a minor child or other dependent, ethical and legal consultation should be sought.

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NOTE: This is the Professional Version. CONSUMERS: View Consumer Version
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