Between January 1982 and December 1985, 355 fiberoptic pouchoscopies were performed in 123 patients with a continent ileostomy. These examinations have been reviewed to determine the effectiveness of the technique as a diagnostic and therapeutic tool. The Olympus GIF-XP pediatric endoscope was used after pouch lavage, and the afferent loop of ileum, the pouch, and (by retroflexion) the nipple valve were examined on each occasion. There were 63 males and 60 females, with a median age of 35 years (range, 16 to 71 years). The median length of follow-up after pouch construction was 36 months (range, 6 to 120 months), and an average of three examinations were performed per patient (range, 1 to 12). Of 127 examinations performed in asymptomatic patients, the pouch was normal in 117 cases, and there was mesh erosion into the pouch in 10 cases. The remaining 228 examinations were for symptoms that included pouchitis (56), difficulty in intubation (47), incontinence (35), follow-up of treated pouchitis (18), parastomal sepsis (22), blood in the stool (13), anemia (8), excess mucus discharge (6), valve prolapse (4), and purulent discharge from the stoma (1). Eighty-four examinations were normal; 144 revealed a likely cause for the symptoms and led to appropriate treatment, which in 45 patients was surgical. Fiberoptic endoscopy was therapeutic in 6 patients in whom it was used on 10 occasions to intubate a pouch with a slipped valve. Radiographic studies were seldom used, with pouchograms being carried out in 16 patients and fistulograms in 5. Only the fistulograms contributed to the assessment of each patient.(ABSTRACT TRUNCATED AT 250 WORDS)