Fasting and postprandial intragastric bile acid concentrations were determined in healthy subjects and in patients with gastric and duodenal ulcer. The results showed great interindividual variation and wide overlapping between groups. Mean bile acid concentrations, fasting and postprandially, were significantly higher in patients with gastric ulcer than in healthy subjects. The differences between gastric and duodenal ulcer patients and between duodenal ulcer patients and healthy subjects were not significant. Fiber-enriched wheat bran reduced bile acid concentrations significantly in patients with gastric ulcer disease.