Aim. The combination of a proton pump inhibitor (PPI) or ranitidine-bismuth-citrate (Rbc) and two antibiotics for 7-10 days are, at present, the preferred treatments in Helicobacter-pylori eradication. However, therapies for fewer than 7 days have been scarcely evaluated and it is unknown whether the length of treatment can be shortened, without a lost of efficacy, if three instead of two antibiotics are used. The aim of our study was to evaluate the efficacy of Rbc plus three antibiotics for only 5 days in H. pylori eradication. Methods. We prospectively studied 80 patients (34% duodenal ulcer, 66% functional dyspepsia) infected by H. pylori. At endoscopy, biopsies were obtained for histological study and rapid urease test, and a C-13-urea breath test was carried out. Urea breath test was repeated 4 weeks after completing eradication treatment with Rbc [400 mg twice a day (bid)], amoxicillin (1 g bid), clarithromycin (500mg bid) and metronidazole (500 mg bid). All drugs were administered together after breakfast and dinner for 5 days only, and no treatment was administered thereafter. Compliance with therapy was determined from the interrogatory and the recovery of empty envelopes of medications. Results. In 79 out of the 80 patients, H. pylori eradication success or failure was assessed after therapy (one patient was lost from follow-up). All but one of these 79 patients took all the medications (one patient stopped treatment on the day 3 due to nausea/vomiting). Per protocol eradication was achieved in 72/78 (92%; 95% CI, 84-96%) and in 72/80 (90%; 81-95%) by intention-to-treat. Therapy was more effective in patients with duodenal ulcer than in those with functional dyspepsia [100% (87-100%) vs. 85% (73-92%) by intention-to-treat; P <.05]. Adverse effects were described in ten patients (12%), and included the perception of a metallic taste (eight patients), nausea/vomiting (two patients, one of them abandoned the treatment due to this), and diarrhea (two patients). Conclusion. The combination of Rbc, amoxicillin, clarithromycin and metronidazole for only 5 days represents a promising therapy for H. pylori infection, due to its high efficacy, simple posology, low cost and excellent tolerance.