Much has been achieved in Helicobacter pylori research, to the point that the growth of new knowledge is bound to slow down. However, expectations for further developments remain high. Knowledge about the characteristic organism and behaviour is already extensive. Particularly intriguing are the differences in genetic make-up in the various geographical regions. Sadly, detailed knowledge on how the organism spreads is still lacking. The spectrum of clinical presentation in humans is largely known. Helicobacter pylori is disappearing worldwide, allowing the relative frequency of H. pylori-negative ulcer disease to increase. The extent to which H. pylori disappearance and eradication is responsible for decreasing prevalence of gastric cancer remains speculative. Antimicrobial therapy is dominated by proton pump inhibitor triple therapy as first line therapy, with quadruple therapy as second rescue line therapy. The long-term consequences of the rising resistance to the 'key' antimicrobials are so far unknown, because few data are available on therapeutic outcomes in routine practice outside pharmaceutical trials. (C) 2000 Blackwell Science Asia Pty Ltd.