Common acceptance that stomach ulcers (peptic ulcers) were caused by too much acid in the stomach.

Barry Marshall and Robin Warren attempt to publish papers directly linking gastric ulcer disease to H. pylori. They meet opposition and rejection before finally succeeding.

Medical guidelines are updated to reflect the link between H. pylori and various types of stomach ulcers. Warren and Marshall are awarded a Nobel Prize in Physiology or Medicine.

The first papers are presented at a conference showing that acid-reducing medications do not cure peptic ulcers.