Answer is A (Diveiculosis) Although anorectal disease is the most commonm cause of bleeding per rectum in the elderly, these lesions usually cause small amount of 'bright red' blood on the surface of stool and toilet tissue (small bleeds). Diveiculosis may give rise to massive colonic bleed. The usual presentation of diveicular hemorrhage is that of brisk painless passage of a maroon coloured stool. It is the most common cause of massive bleeding per rectum in those above 55 years of aze and hence the answer here. Angiodysplasias and diveiculosis were the most common reasons for LGIB Common causes of Acute Lower G.I. bleeding over 55 years of age are : Anorectal disease : Haemorrhoids and fissures Diveiculosis Angiodysplasia Polyps and Cancer Enterocolitis