For decades, it was thought that stress was the main reason a person would get a peptic ulcer. However, Barry Marshall, a Doctor from Australia, was convinced that the medical community was wrong and it actually wasn’t stress that caused stomach ulcers. From biopsying ulcer patients and culturing the organisms in the lab, he traced ulcers and stomach cancer to a specific bacterium, Helicobacter pylori (H. pylori). After conventional methods of trying to prove his hypothesis failed (mice are not affected by H. pylori and experiments on humans are illegal), he drank a petri-dish full of H. pylori with the hopes of giving himself an ulcer to support his theory. Over the next few days he vomited, had bad breath and experienced terrible gastritis. A little over a week later he cultured his own stomach and confirmed that H. pylori had indeed colonized his stomach, which finally showed that bacteria were the underlying cause of stomach ulcers.