Barium examination of the small bowel revealed fixation, dilation, separation of bowel loops and delayed small intestinal transit in nine patients with practolol induced peritonitis. The diagnosis may be first suggested by this examination, and a history of prolonged therapy with beta-blocking agents should be sought in patients showing these changes where no other cause for them can be found. Symptoms may develop up to a year following cessation of therapy so that further cases may still come to light despite the withdrawal of practolol for long-term use. Small bowel barium examination is indicated in patients who have received practolol therapy and who develop suspicious alimentary symptoms.