In the early 1980s, Australian doctor Barry Marshall was convinced that stomach ulcers were caused by bacteria, not stress, as the entire medical establishment believed. Nobody took him seriously. So in 1984, he had an endoscopy to confirm his stomach was healthy, then drank a broth of cultured H. pylori bacteria. Within days he was vomiting, bloated, and had rancid breath. A biopsy confirmed his stomach was now riddled with the bacteria. He took antibiotics and cured himself. The medical establishment still dragged its feet for years, but in 2005 Marshall won the Nobel Prize for a discovery he'd had to prove on his own body.