Timeline of peptic ulcer disease and Helicobacter pylori

In 2005, Barry Marshall and Robin Warren were awarded the Nobel Prize in Physiology or Medicine for their discovery that peptic ulcer disease (PUD) was primarily caused by Helicobacter pylori, a bacterium with affinity for acidic environments, such as the stomach.

A single study, conducted in 1954, did not find evidence of bacteria on biopsies of the stomach stained traditionally; this effectively established the acid theory as dogma.

This paradigm was altered when Warren and Marshall effectively proved Koch's postulates for causation of PUD by H. pylori through a series of experiments in the 1980s; however, an extensive effort was required to convince the medical community of the relevance of their work.

Now, all major gastrointestinal societies agree that H. pylori is the primary nondrug cause of PUD worldwide, and advocate its eradication as essential to treatment of gastric and duodenal ulcers.

Advances in molecular biology in the late 20th century led to the sequencing of the H. pylori genome, resulting in a better understanding of virulence factors responsible for its colonization and infection, on the DNA level.