BACKGROUND/AIMS: To assess the long-term effect of eradication on symptomatic improvement according to the type of antibiotic and the duration of treatment in -associated functional dyspepsia. METHODS: We searched Pubmed, Embase, CINAHL, and the Cochrane library databases for randomized controlled trials written in English and undertaken up to August 2016 that met our eligibility criteria. The search methodology used combinations of the following keywords: OR OR HP; dyspepsia OR functional dyspepsia OR non-ulcer dyspepsia; eradication OR cure OR treatment. The study outcome was the summary odds ratio (OR) for symptomatic improvement in -associated functional dyspepsia with successful eradication therapy. Subgroup analyses were performed based on the type of antibiotic, and the duration of treatment, whether or not patients had symptoms of irritable bowel syndrome, and on race. RESULTS: Sixteen randomized controlled trials met the inclusion criteria. The summary OR for symptomatic improvement in patients in our eradication group was 1.33 (95% confidence interval [CI], 1.16-1.54; < 0.01). In a subgroup analysis on type of antibiotic, symptomatic improvement with metronidazole-containing regimen (OR, 1.87; 95% CI, 1.26-2.77) was better than treatment with clarithromycin (OR, 1.29; 95% CI, 1.11-1.50). eradication therapy given for 10-14 days was the more effective for symptom improvement than 7-day therapy. When the studies excluding irritable bowel syndrome cases were analyzed, there were no therapeutic effects of eradication on symptomatic improvement. CONCLUSIONS: In the clinical setting, the most effective eradication regimen for functional dyspepsia to provide relief of symptoms is a metronidazole-based treatment regimen for at least 10 days. The explanation for this is that -associated functional dyspepsia could be associated with dysbiosis.