Bleeding in stool is usually caused by a complication within the digestive tract, with some specific causes being diverticular disease, colitis, angiodysplasia, peptic ulcers, esophageal complications and polyps. Blood in the stool is not always an indication of a serious complication, but may equally be a result of a simple anal fissure caused by constipation.
One of the causes of blood in the stool may be divercular disease, which refers to tiny pouches that develop in the colon. They are mostly harmless unless infected. Another cause of blood in stool is the development of polyps. These are small growths that may eventually form into cancer.
Another common cause of blood in the stool is the development of ulcers within the digestive tract walls. Ulcers are a result of a bacterial infection and may become painful after a while. Anal fissures also cause blood in stool. However, this may also be characterized by pain since the hard stool presses hard against the walls of the anal lining.
Angiodysplasia refers to a condition in which certain blood vessels become fragile and experience bleeding, which is then noticeable in the stool. Another cause of blood in stool is hemorrhoids, which are a result of swelling of the rectal or anal veins. About 75 percent of people experience this condition at some point in life, according to the National Institute of Diabetes and Digestive and Kidney Diseases. The best way to know the exact cause of blood in stool is by visiting a doctor for proper examination.