Randomised trials have shown that duodenal ulcers treated by H2 blockers heal faster if Helicobacter pylori is eradicated concurrently. It remains unknown whether eradication of H pylori without suppression of acid-secretion, is sufficient to allow healing. 153 patients with H pylori infection and duodenal ulcer were randomised to receive either a 1-week course of bismuth subcitrate, tetracycline, and metronidazole (76), or omeprazole for 4 weeks with the same three-drug regimen for the first week (77). Endoscopy and antral biopsies were done at entry and 4 weeks after treatment. 132 patients were suitable for analysis. Duodenal ulcers healed in 60 (92%; 95% CI 86-100%) patients taking bismuth, tetracycline, and metronidazole compared with 63 (95%; 88-100%) taking omeprazole in addition to the three other drugs. H pylori was eradicated in 61 (94%; 88-100%) who received only three drugs compared with 66 (98%; 96-100%) who received omeprazole as well. Symptoms were reduced more effectively during the first week in patients who received omeprazole (p = 0.003). We conclude that a 1-week regimen of bismuth, tetracycline, and metronidazole for patients with H pylori and duodenal ulcer eradicates the organism and heals the ulcer in most patients. Concurrent administration of omeprazole reduces ulcer pain more rapidly but has no effect on ulcer healing.