Blood in the stools can be caused by many conditions. These include:
--diverticulitis, a condition that causes pockets in the intestine, which can become inflamed and infected
--anal fissure, which is a tear in the lining of the anus
--anorectal fistula, which is a crack in the lining of the anus that extends to the muscle of the anus
--ulcerative colitis, a disease that can cause swelling and sores in the lining of the colon
--bleeding disorders
--abdominal injuries, such as crush injuries from a car accident or a fall
--a foreign body in the colon or rectum
--alcohol abuse
--heavy metal poisoning, such as lead poisoning
--esophageal varices, which are twisted, dilated veins that can cause pain and bleeding in the esophagus
--colorectal polyps, which are tumors in the bowel that may be noncancerous or cancerous
--Crohn's disease, which can cause inflammation in any part of the gastrointestinal tract
--dysentery or other intestinal disorders, such as Meckel's diverticulum or intussusception
--ulcerative proctitis, which is an inflammation of the rectum and anus
--hemorrhoids, which are masses of small, dilated veins in or near the anus
--peptic ulcer, which is an open sore or lesion in the lining of the stomach or small intestine
--colorectal cancer
--food poisoning