Barry Marshall Drank a Petri Dish of Bacteria to Prove Ulcers Are an Infection

Through the 1970s and 1980s, the medical establishment was certain that peptic ulcers were caused by stress, spicy food, and excess stomach acid. The treatment was antacids and H2 blockers; a duodenal ulcer was a chronic, recurring condition that one managed for life. Then a Perth pathologist named Robin Warren noticed in 1981 that biopsy samples from inflamed stomachs were full of curved, motile bacteria nobody had described.

Warren paired up with a 30-year-old gastroenterology trainee, Barry Marshall, and the two co-published their findings in The Lancet in 1984. The paper proposed that the bacterium — they would later name it Helicobacter pylori — was the cause of most peptic ulcers and chronic gastritis. The reception was hostile. Microbiology textbooks taught that nothing could survive the stomach's acid. Pharmaceutical companies sold billions of dollars of antacids a year for a problem they were now being told was an infection.

Marshall ran out of patience. In 1984, he cultured a slurry of H. pylori from a patient's biopsy and drank it. He kept journal notes on himself. By day three he had nausea and bad breath and was vomiting in the morning. By day eight an endoscopy showed massive gastritis and the cultured bacteria thriving along his stomach lining. He treated himself with antibiotics and bismuth, the symptoms cleared, and he had — informally, and on himself — fulfilled Koch's postulates.

The paper detailing the experiment ran in The Medical Journal of Australia in 1985. Acceptance crept in slowly through the 1990s. In 2005 Warren and Marshall shared the Nobel Prize in Physiology or Medicine. The standard treatment for H. pylori ulcers today is a one- to two-week course of antibiotics. Marshall is now 74, codirects the Marshall Centre at the University of Western Australia, and is, by his own description, mostly retired.