What causes bleeding in the digestive tract?
A variety of conditions can cause bleeding in the digestive tract. Causes of bleeding in the upper digestive tract include the following:

• Peptic ulcers. Helicobacter pylori (H. pylori) infections and long-term use of nonsteroidal anti-inflammatory drugs (NSAIDs), such as aspirin and ibuprofen, are common causes of peptic ulcers.
• Esophageal varices. Varices, or enlarged veins, located at the lower end of the esophagus may rupture and bleed massively. Cirrhosis is the most common cause of esophageal varices.
• Mallory-Weiss tears. These tears in the lining of the esophagus usually result from vomiting. Increased pressure in the abdomen from coughing, hiatal hernia, or childbirth can also cause tears.
• Gastritis. NSAIDs and other drugs, infections, Crohn's disease, illnesses, and injuries can cause gastritis—inflammation and ulcers in the lining of the stomach.
• Esophagitis. Gastroesophageal reflux disease (GERD) is the most common cause of esophagitis—inflammation and ulcers in the lining of the esophagus. In GERD, the muscle between the esophagus and stomach fails to close properly, allowing food and stomach juices to flow back into the esophagus.
• Benign tumors and cancer. A benign tumor is an abnormal tissue growth that is not cancerous. Benign tumors and cancer in the esophagus, stomach, or duodenum may cause bleeding.

Causes of bleeding in the lower digestive tract include the following:

• Diverticular disease. This disease is caused by diverticula—pouches in the colon wall.
• Colitis. Infections, diseases such as Crohn's disease, lack of blood flow to the colon, and radiation can cause colitis—inflammation of the colon.
• Hemorrhoids or fissures. Hemorrhoids are enlarged veins in the anus or rectum that can rupture and bleed. Fissures, or ulcers, are cuts or tears in the anal area.
• Angiodysplasia. Aging causes angiodysplasia—abnormalities in the blood vessels of the intestine.
• Polyps or cancer. Benign growths or polyps in the colon are common and may lead to cancer. Colorectal cancer is the third most common cancer in the United States and often causes occult bleeding.