Exsanguination is the loss of blood from the circulatory system of a vertebrate, usually leading to death. The word comes from the Latin 'sanguis', meaning blood,[1] and the prefix 'ex-', meaning 'out of'.
Exsanguination has long been used as a method of animal slaughter. Humane slaughter must ensure the animal is rendered insensible to pain, whether through a captive bolt or other process, prior to the bloodletting.
Depending upon the health of the individual, a person usually dies from losing half to two-thirds of their blood; a loss of roughly one-third of the blood volume is considered very serious. Even a single deep cut can warrant suturing and hospitalization, especially if trauma, a vein or artery, or another comorbidity is involved. In the past, bloodletting was a common medical procedure or therapy, now rarely used in medicine.