Vomiting blood may be caused by:

• Acute liver failure
• Aspirin
• Benign tumors of the stomach or esophagus
• Cirrhosis (scarring of the liver)
• Defects in gastrointestinal tract blood vessels
• Dieulafoy's lesion (an artery that protrudes through the stomach wall)
• Duodenitis, which is inflammation of the top part of the small intestine.
• Esophageal cancer
• Esophageal varices (enlarged veins in the esophagus)
• Esophagitis (inflammation of the esophagus)
• Gastric erosions (breakdown of tissue lining the stomach) due to H. pylori, nonsteroidal anti-inflammatory medications (NSAIDs) or other medications
• Gastric varices (enlarged veins in the stomach) due to liver failure or portal hypertension
• Gastritis (inflammation of the stomach lining)
• Gastropathy (bleeding due to dilated blood vessels in the stomach lining)
• Mallory-Weiss tear (tear in the esophagus associated with pressure caused by vomiting or coughing)
• Nonsteroidal anti-inflammatory drugs
• Pancreatic cancer
• Pancreatitis
• Peptic ulcer
• Portal hypertension (high blood pressure in the portal vein)
• Prolonged or vigorous vomiting
• Stomach cancer

In infants and young children, vomiting blood may also result from:

• Birth defects
• Blood-clotting disorders
• Milk allergy
• Swallowed blood, such as from the nose or from the mother during birth
• Swallowed object
• Vitamin K deficiency

Vomiting blood (hematemesis) refers to significant amounts of blood in your vomit. Small streaks or flecks of blood in material you spit up may come from the teeth, mouth or throat and isn't usually considered vomiting blood. Blood in vomit may be bright red, or it may appear black or dark brown like coffee grounds.

Swallowed blood, as from a nosebleed or forceful coughing, may cause bloody vomit, but truly vomiting blood usually means something more serious and requires immediate medical attention. Bleeding in your upper gastrointestinal tract (mouth, esophagus, stomach and upper small intestine) from peptic (stomach or duodenal) ulcers or torn blood vessels is a common cause of vomiting blood.

Call 911 or your local emergency number if vomiting blood causes dizziness after standing, rapid, shallow breathing or other signs of shock.

Call 911 or emergency medical assistance

Call 911 if vomiting blood causes signs and symptoms of severe blood loss or shock, such as:

• Rapid, shallow breathing
• Dizziness or lightheadedness after standing up
• Blurred vision
• Fainting
• Confusion
• Nausea
• Cold, clammy, pale skin
• Low urine output

Seek immediate medical attention

Ask someone to drive you to the emergency room if you notice blood in your vomit or begin vomiting blood. It's important to quickly identify the underlying cause of the bleeding and prevent more-severe blood loss and other complications, including death.