BackgroundFunctional dyspepsia is thought to be a diagnosis made after excluding endoscopically detectable lesions by the current Rome III criteria. However, whether these functional dyspepsia patients were diagnosed appropriately is still controversial. Materials and MethodsA total of 223 patients diagnosed with functional dyspepsia by Rome III criteria were enrolled. All patients were submitted to endoscopic examination, rapid urease test, and histologic evaluation. We also appraised the effect of a 7-day treatment based on the Glasgow Dyspepsia Severity Score. ResultsHelicobacter pylori infection and neutrophil infiltration were found in 37.7% and 36.3% cases, respectively, and were both more frequent in the subgroup with epigastric pain symptom (EPS) than in the other two subgroups. In addition, neutrophil infiltration was more common and severe in the H.pylori-positive individuals than in the patients without infection (Mann-Whitney U-test=431.500, p<.001). The treatment was useful in symptom improvement of all three subgroups, and the EPS subgroup had the greatest change of symptom scores before and after treatment as compared with the subgroup with postprandial distress symptom (PDS) and PDS/EPS subgroup ((2)=42.745, p<.001), and the eradication of H.pylori revealed a statistical significant difference in different subgroups ((2)=11.300, p=.001). ConclusionsOur findings showed that many H.pylori-positive subjects diagnosed as functional dyspepsia were actually chronic gastritis patients, especially the EPS cases who are more likely to be patients with active gastritis under microscope, and also benefit most from the treatment of proton-pump inhibitors or eradication of H.pylori.