Bleeding in the digestive tract is a symptom of a problem rather than a disease itself. Most causes of bleeding are related to conditions that can be cured or controlled, such as hemorrhoids.
The cause of bleeding may not be serious, but locating the source of bleeding is critical. The digestive or gastrointestinal (GI) tract includes the esophagus, stomach, small intestine, colon, rectum, and anus. Bleeding can come from one or more of these areas -- from a small area such as an ulcer on the lining of the stomach or from a more diffuse problem such as inflammation of the colon.
Varices. Abnormally enlarged veins usually located at the lower end of the esophagus or the upper stomach, called varices, may rupture and bleed massively. Cirrhosis of the liver is the most common cause of esophageal varices.
Mallory-Weiss tear. This is a tear in the lining of the esophagus that usually is caused by prolonged vomiting but may also result from other causes of increased abdominal pressure, such as coughing, hiccupping, or childbirth.
Stomach ulcers and intestinal ulcers. Ulcers in the stomach may enlarge and erode through a blood vessel, causing bleeding. Aside from medication, the most common cause of a stomach ulcer is an infection with a bacterium called Helicobacter pylori. Also, patients suffering from burns, shock, head injuries, or cancer, as well as those who have undergone extensive surgery, may develop stress-related stomach ulcers. Intestinal ulcers are usually caused by excess stomach acid and infection with Helicobacter pylori.