Helicobacter pylori (HP) has been proposed as a mechanism of functional dyspepsia, but its role is still unclear. Our aim was to investigate the association between HP infection and dyspeptic symptoms and to verify whether the infection affects the pathophysiological mechanism of functional dyspepsia. The presence of HP and its association with dyspeptic symptoms were studied in 326 patients. Also, the effect of HP infection on solid/liquid gastric emptying rates, gastric sensitivity, and accommodation to meal was studied. HP was present in 17% of the patients, who showed symptom prevalence similar to that of HP-negative patients. Presence of HP did not significantly affect gastric emptying rates for solids and liquids, discomfort sensitivity thresholds (8.7 +/- 0.3 vs 9.8 +/- 0.9 mm Hg), or meal-induced gastric relaxation (133 +/- 12 vs 125 +/- 29 ml; all P's NS). In conclusion, in patients with functional dyspepsia the presence of HP infection does not seem to affect significantly the overall prevalence of symptoms or the gastric sensory-motor functions.