The aim of this study was twofold: first, to investigate the effectiveness of a standard triple therapy (tripotassium dicitrato bismuthate, 125 mg q.i.d., tetracycline hydrochloride 500 mg q.i.d., and metronidazole 500 mg t.i.d.) in eradicating Helicobacter pylori in patients with duodenal ulcer successfully healed with omeprazole or ranitidine; second, to examine the influence of the eradication on duodenal ulcer recurrence rate after 12 months. Two hundred forty-five consecutive H. pylori-positive patients with healed duodenal ulcer either with omeprazole (20 mg/day, 126 patients) or with ranitidine (150 mg b.i.d., 119 patients) given at random, began triple therapy for 15 days. H. pylori eradication was looked for 4-5 weeks later by culture of biopsy material, hematoxylin-eosin stain, and rapid urease test. H. pylori-eradicated patients were followed up for 12 months. Endoscopy was carried out at the end of the follow-up or whenever symptoms appeared. Five patients (2.0%) withdrew because of triple-therapy-related side effects. The eradication rate was 92% (220 of 240 patients); no difference was found between those healed with omeprazole (93%, 114 of 123 patients) or ranitidine (91%, 106 of 117 patients). Of 220 successfully treated patients, 132 completed the 12-month follow-up. The duodenal ulcer recurrence rate was 4% (5 of 132 patients); 3% (2 of 70) in the omeprazole group and 5% (3 of 62) in the ranitidine group healed. All the recurrences were asymptomatic. H. pylori recurrence rate was 11% (14 of 132 patients); no difference was found between patients healed with omeprazole (10%, 7 of 70 patients) or with ranitidine (11%, 7 of 62 patients). All the recurrent duodenal ulcers occurred in H. pylori-positive patients (36%, 5 of 14 patients). Standard triple therapy after duodenal ulcer healing with omeprazole or ranitidine eradicates H. pylori in comparable high rates. Side effects were mild and dropouts were only 2%. Ulcer recurrence rate 12 months after eradication was low and comparable between those healed with omeprazole or ranitidine.