The site of recurrent duodenal ulcer. The aim of this retrospective study was to determine the site of recurrent duodenal ulcer in relation to the site of the index ulcer. One hundred and thirty-five patients who had recurrent duodenal ulcer after documented healing of an index ulcer were studied. The recurrent ulcer was more likely to occur in the anterior bulb if the index ulcer was anterior (35 of 58 = 60%) than if the index ulcer was not anterior (29 of 77 = 38%, p less than 0.01). However, the likelihood of a recurrent ulcer on the posterior wall of the bulb was not significantly different whether the index ulcer was posterior (11 of 36 = 31%) or not (22 of 99 = 22%, p less than 0.24). Three of 20 patients (15%) who initially presented with bleeding bled again with their recurrent ulcers, compared with eight of 115 patients (7%) who first presented with dyspepsia only (p = 0.39). Thirteen patients were assessed independently by two endoscopists to determine ulcer site. Their assessments concurred for 12 (92%). 