Although the aetiopathogenetic role of Helicobacter Pylori (HP) in duodenal ulcer and in chronic gastritis seems now well defined, we have not yet standardized therapeutic schedules to achieve disappearance of HP. This study was aimed at evaluating the efficacy of two different therapeutic schedules, colloidal bismuth alone [CB(1200 mg/day)], vs. association with amoxicillin [CB+A(3 g/day)] for six weeks, to clear HP from antral specimens in a cohort of dyspeptic patients. 49 consecutive patients (23 females, 26 males, mean age 47 years, range 22-69) with HP in gastric specimens, 30 suffering from chronic antral gastritis (CG) and 19 affected by duodenal ulcer (DU) were treated with CB (37 pts) or with CB+A (12 pts). DU patients were given also H2-blockers. These latter patients were all healed at the endoscopic control performed after therapy. 4 out of 13 DU patients (31%) treated with CB were found HP free. In 4 out of 6 DU patients (66%) treated with CB+A, HP was no more detectable. As for CG patients, 12 out of 24 (50%) were free from HP at control when treated with CB, while only 2 out of 6 (33%) when CB+A was administered. This study suggests that colloidal bismuth is more effective when administered associated with amoxicillin, but this concerns only DU patients. No relation between endoscopic healing of UD and HP presence was found.