The refusal of blood transfusions is a religiously grounded practice most prominently associated with Jehovah's Witnesses, who decline transfusions of whole blood and its primary components, red cells, white cells, platelets and plasma, even in situations where physicians judge a transfusion necessary to save life. The refusal rests on their interpretation of biblical passages commanding abstention from blood: the instruction given to Noah, the prohibition in the Law of Israel against eating blood, and the decree of the early Christian council recorded in the Book of Acts that believers should "abstain from blood." Jehovah's Witnesses understand these as a standing command that extends to the taking of blood into the body by transfusion, and regard obedience to it as a matter of the deepest religious conviction, a mark of faithfulness to God that takes precedence over the prolonging of earthly life.
The practice has posed serious and much-debated questions at the intersection of religion, medicine, ethics and law, above all where it concerns the refusal of life-saving treatment, and most acutely where children are involved and parents decline transfusion on their behalf. Courts in many countries have generally upheld the right of competent adults to refuse treatment for themselves on religious grounds, while frequently intervening to authorise transfusion for minors against their parents' wishes, holding the child's life to override the parents' religious objection. The position has also spurred significant developments in medicine: the demand for alternatives has advanced the field of "bloodless" surgery and blood-conservation techniques, and Jehovah's Witnesses maintain liaison structures to work with medical staff. The practice stands as a notable case of a religious conviction that requires its adherents to accept grave risk rather than violate what they hold to be a divine command.