Colonic motility study was performed on a total of 145 patients. Of these, 55 were patients with symptomatic complicated diverticular disease, 30 had symptomatic uncomplicated diverticular disease, 30 had asymptomatic diverticular disease, and 30 were controls. The pressure sensors were positioned in the descending and the true sigmoid colon. Colonic motility index was significantly higher in symptomatic rather than in asymptomatic diverticular disease in the resting (P less than 0.001) and postprandial (P less than 0.001) states. This confirmed the association between symptomatic diverticular disease and high intraluminal pressure. The patients of the subgroup--complicated diverticular disease--were relatively young (mean age: 51.1 +/- 2.02 years) and had a short history of abdominal pain (18-36 months) and a short segment of colon with diverticula (cm 7.25 +/- 1.31). Our observations suggest that patients showing these indicators are at risk for major complication.