Collagenous colitis is characterized by watery diarrhea and inflammatory infiltration associated with a subepithelial collagen deposit on colonic biopsies despite a normal or subnormal endoscopic appearance. We here describe 5 patients treated with the locally active steroid budesonide. Complete and partial response was observed in 3 and 2 patients, respectively. Budesonide thus seems to be of therapeutic benefit in collagenous colitis. Prospective randomized long-term studies are needed to support this hypothesis.