The Catholic Church places no prohibition on blood transfusions and regards them as an acceptable medical intervention consistent with the duty to care for one's health and life. Catholic moral theology grounds its bioethical approach in natural law and the dignity of the human person. The Catechism (§2288) affirms: 'Life and physical health are precious gifts entrusted to us by God. We must take reasonable care of them.'

Catholic bioethics distinguishes between ordinary and extraordinary means of medical treatment: ordinary means (proportionate treatments with reasonable hope of benefit) are morally obligatory; extraordinary means (disproportionate burdens with little hope of benefit) may be refused. Blood transfusions are typically considered an ordinary medical treatment. The Pontifical Academy for Life has addressed numerous bioethical questions in this spirit. The contrast with the Jehovah's Witnesses' absolute prohibition on transfusions could not be more stark from a Catholic perspective.