In July 1984, gastroenterologist Barry Marshall took a bold and unusual step to prove a controversial theory. He drank a cloudy beef broth containing Helicobacter pylori, a bacterium, in one gulp. Marshall, working at Fremantle Hospital in Australia, did this to demonstrate that the bacteria could cause gastric ulcers, not stress or excess stomach acid as was commonly believed at the time. Before consuming the broth, Marshall had a control endoscopy, which showed a healthy stomach lining. Within days, he began experiencing symptoms like nausea and a loss of stomach acid, and his mother noticed he had bad breath. By the eighth day, a follow-up endoscopy confirmed gastritis and the presence of H. pylori. Marshall then waited a few more days before starting treatment with antibiotics and bismuth, beginning on the fourteenth day. Marshall’s experiment was met with skepticism from his peers, and not without reason. In the 1980s, the prevailing belief was that ulcers were caused by stress or high stomach acidity, not by an infection. Patients were often treated with antacids, antidepressants, or even psychotherapy. The idea that a bacterium could survive in the highly acidic environment of the stomach seemed impossible. However, H. pylori has a unique adaptation: it produces an enzyme called urease, which breaks down urea into ammonia and bicarbonate. This process creates a protective layer of neutral pH around the bacteria, allowing it to survive and attach to the stomach lining. This mechanism was not known in the 1970s and helped explain how the bacterium could cause ulcers. It took years for the medical community to accept Marshall’s findings. For decades, ulcers were considered a mechanical issue, and treatments often involved invasive surgeries like vagotomies, which cut nerves that stimulate acid production, or partial gastrectomies, which removed parts of the stomach. These procedures often led to long-term digestive problems, including nutritional deficiencies and chronic discomfort. While stress and anti-inflammatory drugs can play a role in some cases, H. pylori is now recognized as the primary cause of most ulcers. In 2005, Barry Marshall and his collaborator, Robin Warren, were awarded the Nobel Prize in Physiology or Medicine for their discovery of the role of H. pylori in ulcers and gastritis. This recognition came 21 years after Marshall’s self-experiment in Fremantle. It wasn’t until 1994 that a major medical conference in the United States officially confirmed that H. pylori was the main cause of ulcers, not stress. Today, the treatment of choice for most ulcers is the eradication of H. pylori with antibiotics, avoiding the need for unnecessary surgery that was once common.