Hematemesis is the vomiting of blood. It is always an important sign. It can be confused with hemoptysis (coughing up blood) or epistaxis (nosebleed), which are more common. The source is generally the upper gastrointestinal tract, typically above the suspensory muscle of duodenum. It may be caused by ulcers, tumors of the stomach or esophagus, varices, prolonged and vigorous retching, gastroenteritis, ingested blood (from bleeding in the mouth, nose, or throat), or certain drugs.Hematemesis is treated as a medical emergency, with treatments based on the amount of blood loss. Investigations include endoscopy. Any blood loss may be corrected with intravenous fluids and blood transfusions. Patients may need to avoid taking anything by mouth. Definition
Hematemesis is the vomiting of blood. This is usually vomit that contains bright red blood. Coffee ground vomiting is similar to hematemesis, but is distinct in not involving bright red blood.Hematemesis is always an important sign. It must be differentiated from hemoptysis (coughing up blood) and epistaxis (nosebleed). Both of these are more common conditions. These may be difficult to distinguish. Differential diagnosis
Hematemesis may be caused by:

Peptic ulcer. This may be related to Zollinger–Ellison syndrome, which causes severe disease. Vascular malfunctions of the gastrointestinal tract, such as bleeding gastric varices or intestinal varices. Mallory-Weiss syndrome: bleeding tears in the esophagal mucosa, usually caused by prolonged and vigorous retching. Vomiting of ingested blood after bleeding in the mouth, nose, or throat. Tumors of the stomach or esophagus. Irritation or erosion of the lining of the esophagus or stomach. Radiation poisoning. Viral hemorrhagic fevers.
kidney, brain, or gangrene of arms or legs). An untreated patient could develop cerebral atrophy. Minimal blood loss
In cases that do not involve shock, treatment may involve proton pump inhibitors (such as omeprazole) to treat stomach ulcers if they are present. This is given until endoscopy can be arranged. Blood transfusions may be given if the level of hemoglobin in the blood is extremely low, that is less than 8.0 g/dL or 4.5–5.0 mmol/L. A patient may be kept nothing by mouth (or no eating or drinking). Adequate venous access (such as with large-bore cannulas or a central venous catheter) is generally obtained in case the patient develops a further bleed and becomes unstable. Significant blood loss
In a "hemodynamically significant" case of hematemesis, there may be shock. Resuscitation is an immediate priority to prevent death. Intravenous fluids and blood transfusions can be given, preferably by large bore intravenous cannula. The patient is prepared for emergency endoscopy, which is typically done in a operating theatre. Surgical opinion is usually sought in case the source of bleeding cannot be identified endoscopically, and laparotomy is necessary. Securing the airway is a top priority in hematemesis patients, especially those with a disturbed conscious level (hepatic encephalopathy in esophageal varices patient). This may be achieved with a cuffed endotracheal tube. Octreotide may be used if bleeding may be caused by varices. Techniques
Hematemesis, melena, and hematochezia are symptoms of acute gastrointestinal bleeding.