Thirty consecutive patients with endoscopically proven duodenal ulceration who had Helicobacter pylori infection on culture and histology, were treated with tripotassium dicitrato bismuthate (1 tablet q.d.s., 400 mg metronidazole t.d.s. and 500 mg tetracycline t.d.s. for one week, followed by the bismuth salt for a further 3 weeks. All patients were endoscoped at entry and 4 weeks after cessation of treatment, to check for ulcer healing and H. pylori eradication. Two antral biopsies were taken at each endoscopy for histological and microbiological evidence of H. pylori infection. Complete healing of duodenal ulcers was observed in 27/30 patients (90%). Gastritis improved or completely resolved in 26 patients. Eradication of H. pylori was achieved in 27 patients. Of the three patients who failed to heal, two were H. pylori-positive at follow-up and one was H. pylori-negative.