bleeding bleeding bleeding, hemorrhage, haemorrhage or blood loss, is blood escaping from the circulatory system from damaged blood vessels. bleeding can occur internally, or externally either through a natural opening such as the mouth, nose, ear, urethra, vagina or anus, or through a puncture in the skin. hypovolemia is a massive decrease in blood volume, and death by excessive loss of blood is referred to as exsanguination. typically, a healthy person can endure a loss of 10–15% of the total blood volume without serious medical difficulties (by comparison, blood donation typically takes 8–10% of the donor's blood volume). the stopping or controlling of bleeding is called hemostasis and is an important part of both first aid and surgery. for the deliberate extraction of blood, see bloodletting. for other uses, see bleeding (disambiguation). bleedingother nameshemorrhaging, haemorrhaging, blood lossa bleeding wound in the fingerspecialtyemergency medicine, hematologycomplicationsexsanguination, hypovolemic shock, coma, shock types upper head intracranial hemorrhage – bleeding in the skull. cerebral hemorrhage – a type of intracranial hemorrhage, bleeding within the brain tissue itself. intracerebral hemorrhage – bleeding in the brain caused by the rupture of a blood vessel within the head.