Hematemesis or haematemesis is the vomiting of blood. The source is generally the upper gastrointestinal tract, typically above the suspensory muscle of duodenum. Patients can easily confuse it with hemoptysis (coughing up blood), although the latter is more common. Hematemesis "is always an important sign". Vomited blood volumes in excess of 5.5 litres could be life-threatening.