The three types of diverticular disease are true, false, and pseudodiverticula. Most diverticula occur in the distal sigmoid colon in the presence of long-standing constipation. From the prolonged effort of moving small, hard stools along, the muscular layer becomes hypertrophied, rigid, thick, and fibrous. High intraluminal pressure is needed to propel stool through the colon, but this same pressure can force the mucosa through a preexisting area of weakness in the wall, producing a diverticula. Most individuals are asymptomatic and require no treatment except for a high fiber diet or fiber supplements such as bran. Some may complain of abdominal pain lasting hours to days and relieved by passing flatus or feces. Because these events are often accompanied by either diarrhea or constipation, a constellation of symptoms also found with the condition of irritable bowel, it is speculated that there may be a relationship between the two diseases.