The role of Helicobacter pylori infection in proximal gastric motor function and its relation to symptoms in patients with functional dyspepsia is still unclear. We prospectively studied 26 patients with dyspepsia, no structural abnormalities found during endoscopy and biopsy-proven Helicobacter pylori-positive gastritis before and three months after Helicobacter pylori treatment. We used an 11-item score list to evaluate symptoms, gastric biopsies for histology, and a gastric barostat (isobaric inflation-deflation) for proximal gastric motility. Minimal distending pressure (MDP), mean gastric volume at operating pressure, AUC of inflation-deflation cycles, and hysteresis (difference in AUC during inflation and AUC during deflation) were calculated. After three months, Helicobacter pylori was eradicated in 96% of patients. MDP, mean gastric volume at operating pressure, gastric compliance, and hysteresis did not change significantly. Aggregate symptom score as well as histology scores in antrum and corpus decreased significantly. Reduction in postprandial pain correlated with a change in hysteresis (r = 0.567, P < 0.01), but other symptoms did not. Reduction of corpus inflammatory activity correlated with changes in hysteresis (r = 0.604, p < 0.005), suggesting that the stomach attains it original shape faster when inflammation is reduced. These observations suggest that inflammatory changes or release of inflammatory substances associated with Helicobacter pylori infection may influence proximal gastric motor characteristics.