Duodenal bulb acidity and the natural history of duodenal ulceration.

Fasting and post-prandial duodenal bulb pH was recorded in 10 subjects with untreated duodenal ulcers (DU), 10 subjects with healed DU, and 15 healthy volunteers. During fasting, pH was less than 4 for a greater percentage of time in healed than in active DU. Ingestion of a solid test meal accentuated this difference: subjects with active DU and controls both showed less bulb acidification than subjects with healed ulcers. Bulb pH was similar in patients with active ulceration and controls. The finding of neutral bulb pH with active ulceration and low bulb pH with healing may explain the typical cycle of spontaneous healing and relapse in duodenal ulcer disease.