Endoscopic therapy can be employed and may be useful in inflammatory bowel disease patients with dysplastic polyps, inflammatory strictures (enteric and biliary), bleeding, and for treatment of some complications of continent ileostomies. Dysplastic polyps can be removed endoscopically safely and effectively without resorting to colectomy, as long as there is no other detectable dysplasia in flat mucosa and complete removal can be assured (by biopsy of adjacent mucosa and close follow-up). Some colonic strictures in Crohn's disease can be dilated using endoscopes of graded caliber or with through-the-scope balloons, with or without stent placement. Endoscopy is most useful in dilating anastomotic strictures and less useful for long strictures in active inflammatory disease. Strictures in ulcerative colitis are suspicious for neoplasia and, if dilated at all, should be biopsied extensively and followed closely. We prefer colectomy to endoscopic dilatation for strictures in ulcerative colitis. Biliary endoscopy can be used to dilate strictures in primary sclerosing cholangitis and to sample these areas for malignancy. Although dilatation may improve morbidity and prolong survival, it may not prevent progression to cirrhosis. In cholangiocarcinomas, endoscopic dilatation with or without stents can offer palliation and perhaps be used to deliver photodynamic therapy. Injection and sclerotherapy can be employed in Crohn's disease bleeding from a discrete site. In obstructed continent ileostomies (both Kock pouches and pelvic ileoanal reservoirs), endoscopy can be employed effectively to both determine the cause of the obstruction and re-establish patency. We do not advocate endoscopic treatment of toxic megacolon because of the heightened risk of perforation. Endoscopic therapy of Crohn's fistulas is a possible emerging technology, but it has not been used in large cohorts of patients.