["The importance of esophageal acid control in the management of Barrett's esophagus is controversial. The objective of this study was to assess the impact of esophageal acid control on the symptoms of reflux disease, healing of erosive esophagitis, change in length of Barrett's epithelium, and the appearance of squamous islands.", "Thirteen of 27 patients on 60 mg lansoprazole underwent ambulatory 24 h esophageal pH monitoring while on therapy. Symptoms were recorded, and the length of Barrett's epithelium was measured, photographed, and biopsied every 6 months over an average of 5.7 yr.", "Eight of 13 patients had a normal 24 h pH (group I, mean pH < 4, 0.8%), five patients had abnormal results (group II, mean pH < 4, 10.6%). Symptoms improved in all patients, and there was complete healing of erosive esophagitis in all patients. An increase in the number of squamous islands was noted in 62.5% of patients in group I and in 80% of patients in group II. The mean length of Barrett's epithelium at baseline and study completion in group I was 5.6 and 5.0 cm, respectively (mean decrease, 0.6 cm), and for group II was 4.2 and 4.2 cm, respectively (mean decrease, 0 cm). There was no significant difference in the change in length between the two groups (p = 0.494)."] Does normalization of esophageal pH with high-dose proton pump inhibitor therapy result in regression of Barrett 's esophagus?