<prompt> Fuctional GI disorders can be differentiated from organic GI disorders byAbdominal painDiarrheaTenesmusBleeding PR  <response>: Common causes of Bleeding per rectum hemorrhoids anal fissures tears in the rectal tissue, diveicula diveiculitis, including Meckels diveiculum, infections bacterial and other pathogens inflammatory bowel diseases Crohns disease and ulcerative colitis, angiodysplasia fragile blood vessels, tumors,polyps, and bowel trauma. Less common causes include upper GI tract problems like ulcers and Mallory-Weiss tears in the esophagus or a dilated vein or varix. Ref: 