The upper GI tract includes the stomach, mouth, throat, esophagus, and the first part of the small intestine. Blood that is vomited may come from any one of these places.
For example, vomiting that is very forceful or continues for a very long time may cause a tear in the small blood vessels of the throat or the esophagus, producing streaks of blood in the vomit.
Swollen veins in the walls of the lower part of the esophagus, and sometimes the stomach, may begin to bleed. These veins are present in people with severe liver damage.
Other causes may include:
- Bleeding ulcer in the stomach, first part of the small intestine, or esophagus
- Defects in the blood vessels of the GI tract
- Swelling, irritation, or inflammation of the esophagus lining (esophagitis) or the stomach lining (gastritis)
- Swallowing blood (for example, after a nosebleed)
- Tumors of the stomach or esophagus