BACKGROUND/AIMS The aim of this study was to determine the one-year outcome of an eradication therapy with ranitidine bismuth citrate and antibiotics in Helicobacter pylori-positive duodenal ulcer patients in respect to ulcer and Helicobacter pylori relapse rates. METHODOLOGY This multicenter, randomized, double-blind study involved 648 duodenal ulcer patients and had been carried out to compare the following regimens: ranitidine bismuth citrate b.i.d. co-prescribed with either clarithromycin 250 mg q.i.d. or clarithromycin 500 mg b.i.d. or clarithromycin 500 mg b.i.d. plus metronidazole 400 mg b.i.d. for 2 weeks, followed by a further 14 days of treatment with ranitidine bismuth citrate 400 mg b.i.d. to facilitate ulcer healing. H. pylori eradication was assessed by 13C-urea breath test and histology at least 4 weeks, 26 weeks and 52 weeks after the end of treatment. Ulcer relapse and H. pylori status were assessed 4 weeks, 26 weeks and 52 weeks post-treatment or if ulcer symptoms recurred. For the remainder of the follow-up period only serious adverse events were collected. RESULTS At 12 months data of 438 (69%) patients were evaluable. The observed H. pylori eradication rates were 88-91%. H. pylori relapse rates were 2.1% after 26 weeks and 3.9% after 52 weeks. At the week 26 visit 26 patients (5.6%) and at the week 52 visit 25 patients (5.7%) had documented gastroesophageal reflux disease. CONCLUSIONS Our data confirm the reduction of duodenal ulcer relapses after the cure of Helicobacter pylori infection.