The nature of the relationship between Helicobacter pylori infection and reflux oesophagitis is still not completely understood. To review the available evidence from the literature concerning the relationship between Helicobacter pylori infection and reflux oesophagitis with or without Barrett's metaplasia, we performed a Medline search to discover all published reports available in this field since the first description of Helicobacter pylori (1984) to April 1998. A total of 37 papers were found addressing the issue. From the available data, it can be concluded that Hp infection has probably only a minor protective role against the development of reflux oesophagitis. The related mechanisms are, however, still to be clarified. The presence of Helicobacter pylori infection is also likely to increase the efficacy of PPI drugs and, conversely, the eradication of the bacterium decreases the drug effect. The bacterial production of ammonia is the most likely factor explaining this observation. Furthermore, it is now sufficiently clear that patients placed on long-term PPI therapy develop atrophic gastritis only if Helicobacter pylori infection is not eradicated. Finally, both the development of metaplastic changes and the progression to severe dysplasia and adenocarcinoma in Barrett's oesophagus patients are phenomena not related to the presence of Helicobacter pylori antral or oesophageal colonization.