AlphaMED Resources · https://alphamedicine.uk/Resources/glossary/acts-omissions

Acts and omissions

Acts and omissions is the distinction between causing harm by doing something and allowing harm by not doing it.

Updated 19 October 2026 (1 minute read)

Summary

  • An act brings about harm, such as giving a drug that kills. An omission is failing to act, so that harm from an existing illness is allowed to happen.
  • Many lawyers and ethicists treat the two differently, though the line between them is contested.
  • Stopping a treatment is not always easy to classify. Switching off a ventilator involves a positive step, so it is not always clear whether it is an act or an omission.
  • Some argue the outcome matters more than the route, so a death caused by an omission is no less a death.
  • The distinction alone does not decide whether a decision is lawful or ethical. Consent, capacity and best interests also apply.

In practice

  • In Airedale NHS Trust v Bland (1993), Lord Goff said that discontinuing life support can properly be categorised as an omission, which is not unlawful unless it breaches a duty to the patient, and that stopping it is no different from never starting it.
  • Lord Goff contrasted this with giving a drug to bring about a patient's death, which he said was not lawful even when prompted by a humanitarian desire to end the patient's suffering. The Doctrine of double effect page covers drugs given to relieve symptoms that may also shorten life.

Interview questions

  • What do you know about the difference between acts and omissions?
  • A patient asks for their ventilator to be switched off. As the doctor on the ward, how would you explain the difference between stopping treatment and never starting it?
  • Does the distinction between acts and omissions matter morally, or only legally?

Sources

  1. Global Health and Human Rights Databaseglobalhealthrights.org/…/HL-1993-Airedale-NHS-Trust-v.-Bland.pdf

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Related

Doctrine of double effect The doctrine of double effect says an action with a good aim can be acceptable even if it has a harmful side effect that was foreseen but not intended. Best interests Best interests is the test used to make a decision for someone who cannot make it themselves. Life sustaining treatment Life sustaining treatment is any treatment needed to keep a patient alive. Informed consent Informed consent is a patient's agreement to a treatment, given freely, with capacity, and with the information they need.

More NHS hot topics, medical ethics case studies and medical school interview questions are in AlphaMED Resources, which we add to and update through the application cycle.