A doctor drank a beaker of bacteria to prove ulcers weren't caused by stress

In 1984, gastroenterologist Barry Marshall swallowed a petri dish of Helicobacter pylori after colleagues dismissed his claim that a bacterium, not stress or spicy food, caused stomach ulcers. Within days he developed gastritis, confirmed by endoscopy and biopsy, then cured himself with antibiotics. The stunt helped overturn decades of medical dogma and won Marshall and Robin Warren the 2005 Nobel Prize in Physiology or Medicine.

— Barry Marshall and Robin Warren, Barry Marshall — Medical Journal of Australia, 1985