<prompt> Massive colonic bleeding in a patient of diverticulosis is fromInferior mesentric arterysuperior mysentric arterycoeliac arteryGastro duodenal artery  <response>: Although diverticulosis involves mainly the left side of colon, bleeding occurs mostly from right side of colon. Right side is supplied by superior mesentric artery.Hemorrhage from a colonic diverticula is the most common cause of hematochezia in patients over the age of 60. - Harrison 16e, p 1796 