['New triple therapy for eradication of Helicobacter pylori based on a proton pump inhibitor (PPI) provides a cure rate of approximately 90% with few adverse effects. Recently, a PPI-based quadruple therapy, which consists of a PPI plus bismuth-based triple therapy for 7 days, has been studied, and a sufficient eradication rate has been achieved. However, a shorter duration results in improved compliance. In this study, newly developed short-term, simple twice-daily quadruple therapy consisting of rabeprazole, amoxicillin, clarithromycin, and metronidazole (RACM) was compared with a PPI-based triple-therapy regimen for eradication of H. pylori.', 'This study was designed as a randomized open, prospective single-center study. Of a total of 105 H. pylori-positive patients, 55 received the RACM regimen for 5 days (rabeprazole, 10 mg bid; amoxicillin, 750 mg bid; clarithromycin, 200 mg bid; and metronidazole, 250 mg bid), and 50 received the RAC regimen for 5 days (rabeprazole, 10 mg bid; amoxicillin, 750 mg bid; and clarithromycin, 200 mg bid). Cure of the infection was assessed by HpSA (H. pylori stool antigen immunoassay) 1 month after completion of therapy.', 'The rates of eradication of H. pylori by RACM versus RAC were 94.5% (95% CI, 85-99) versus 80.0% (95% CI, 66-90) by intention-to-treat analysis; 98.1% (95% CI, 90-100) versus 87.0% (95% CI, 74-95) by all-patients-treated analysis; and 98.1% (95% CI, 90-100) versus 86.7% (95% CI, 73-95) by per-protocol analysis. No major adverse effects were reported, and 98.0% of patients reported complete compliance.'] Does addition of metronidazole to rabeprazole-amoxicillin-clarithromycin regimen for Helicobacter pylori infection provide an excellent cure rate with five-day therapy?