Bleeding, technically known as hemorrhaging or hæmorrhaging , is blood escaping from the circulatory system. Bleeding can occur internally, where blood leaks from blood vessels inside the body, or externally, either through a natural opening such as the mouth, nose, ear, urethra, vagina or anus, or through a break in the skin. Hypovolemia is a massive decrease in blood volume, and the complete loss of blood, causing death, is referred to as exsanguination. Typically, a healthy person can endure a loss of 10â15% of the total blood volume without serious medical difficulties . The stopping or controlling of bleeding is called hemostasis and is an important part of both first aid and surgery.