Epidemiological, pathophysiological and therapeutic studies have been carried out in order to try and establish whether an association between H. pylori infection and non-ulcer dyspepsia exists. A meta-analysis of pooled data showed that the prevalence of H. pylori infection in dyspepsia was higher than in controls (odds ratio 2.3), but this may be explained by selection bias. No convincing symptom profiles have been found to be associated with the infection, and there have been no consistent observations regarding the effects of the infection on gastroduodenal motility or sensation. Clinical trials in adults have been equivocal. Although a recent meta-analysis identified an overall benefit of H. pylori therapy, only selected trials could be included. Some studies have suggested that significant symptom improvement requires up to 12 months follow-up to be documentable. Little relevant paediatric clinical trial data are available. While it is possible that H. pylori may be responsible for symptoms in a small proportion of patients with non-ulcer dyspepsia and in some of these cases anti-H. pylori therapy may be beneficial, this remains to be established.