The purpose of this study was to compare the clinical features in Helicobacter pylori patients to-infected with Schistosuma or Fascivla with those infected with H. pylori alone. The study was carried out on 90 indi- Yiduals fronu t11C Internal Medicine, Tropical Medicine and Hepatology Departments of Mansoura and Benha University Hospitals, Egypt. Partici-pants were divided into six groups, cach af 15 subjects: schistosomiasis, fascioliasis, H. pylori alone, H. pylori/ schistosomiasis, 11. pylori/fascioliasis patients, and parasite free healthy controls. Patients were diagn04éd ac-cording to standard diagnostic critc-ria. Gastric or duodénal pathological damageswere statistically significantly higher in I-I. pylori patients co-infecLcd with schistosomiasis or fascioliasis pn(lenty; collil)ltred to pullcnis Infcc(ed with helminths alone or thc healthy controls. Patients infected with H. py- lari alone showed less intense gastric and duodenal pathologies. Gastric mucosal damage was comparable in H. pylori/schistosomiasis, as in H. py-Iori/fasciotlasis co-infected patients. The significantly increased gastrodut)- (Ional injuries observed with concur-rent helminth and H. pylori demonstratc that thc pathogenesis of H. pylori infection is negatively af-fccted by a concurrent inlOction with Schistosoma or Fasciola and that helminth infection may be a risk fac-tor for aggravated H. pylori outcome. Control of helminth infections should be the first priority in patients with H. pylori infection.