Quadruple Therapy Versus Dual Therapy as Rescue Regimens for Helicobacter Pylori Infection

Inclusion Criteria: * Patients aged from 18 to 80 years, who presented with upper gastrointestinal symptoms and endoscopically proven H. pylori-positive non-ulcer dyspepsia, were recruited into the study. Exclusion Criteria: * patients with peptic ulcer, * previous H. pylori eradication treatment, * previous gastric surgery, * pregnancy, * lactation, * major systemic diseases, * receipt of anti-secretory therapy, * antibiotics or bismuth in the preceding four weeks, or - allergy to any one of the medications in the regimen.