R v Adams [1957] is an English case that established the principle of double effect applicable to doctors: that if a doctor "gave treatment to a seriously ill patient with the aim of relieving pain or distress, as a result of which that person's life was inadvertently shortened, the doctor was not guilty of murder" where a restoration to health is no longer possible. Such medicines are among those sometimes used in palliative care (the branch of medicine focussed on the relief of pain), most commonly for the most severe pain.

The case narrowly distinguished and approved the binding precedent R v Dyson which confirms it is no defence, in itself, in offences of homicide, that the victim was already dying from an illness if the defendant's conduct has accelerated death. Doctors have an absolute defence to this where they have "properly" eased the suffering of the patient.