Gastrointestinal bleeding may be caused by a variety of medical issues, such as anal fissure, hemorrhoids or intestinal polyps, states MedlinePlus. Additional causes include cancer of the small intestine, colon or stomach, along with esophagitis, gastric ulcer, diverticulosis and Chron's disease.
Other possible causes of gastrointestinal bleeding are radiation treatment, angiodysplasia, esophageal varices and a bowel that has telescoped on itself, explains MedlinePlus. Gastrointestinal bleeding can occur at any area of the gastrointestinal tract. This type of bleeding is generally divided into two distinct groups or areas. The first group or area is upper gastrointestinal bleeding, which occurs in the esophagus, the beginning of the small intestine or in the stomach. The second group or area is lower gastrointestinal bleeding, which occurs in the rectum, anus, large intestine and much of the small intestine.
Signs of gastrointestinal bleeding are stools that look black or tarry, vomiting of blood, small amounts of blood on toilet tissue or in the toilet bowl, and large amounts of blood. Small amounts of blood from gastrointestinal bleeding can cause conditions such as anemia, while large amounts of blood can indicate a medical emergency. Seek medical attention for black or tarry stools, blood in the stool, vomiting blood, or for vomit that resembles coffee grounds.