Gastritis caused by Helicobacter pylori (HP) is common in patients with nonulcer dyspepsia (NUD), but an etiologic relationship between the histologic lesion and clinical symptoms is unproven. HP is inhibited by bismuth subsalicylate (BSS), a traditional remedy for dyspeptic complaints. The aim of this study was to assess the short- and long-term effects of BSS on HP, gastritis, and symptoms in patients with NUD. One hundred twenty-six patients with NUD who were shown to be infected with H. pylori (HP+) were enrolled. There was a two-week placebo run-in period to eliminate placebo responders. Fifty patients remained symptomatic and were randomly assigned to therapy with either BSS liquid or a matching placebo. EGD, biopsy, and clinical evaluations were performed at entry, at week 5 (end of therapy), at week 9 (four weeks after therapy), or at time of symptomatic relapse. Twenty-seven patients received placebo and 23 patients received BSS. BSS suppressed H. pylori in 15/23 patients (65%) and eradicated it in one patient, whereas the placebo had no effect on H. pylori. Gastritis improved during therapy with BSS but relapsed by week 9. There was no significant change in level of dyspeptic symptoms during or after treatment, although one month after the end of treatment, the patients in the BSS group consistently had lower symptom scores and fewer symptomatic days for all symptoms measured. The study confirms that BSS given for three weeks suppresses but does not usually eradicate H. pylori. Such short-term suppression of H. pylori heals gastritis but does not result in clinical improvement.