Professor Barry Marshall did. In the 1980’s, Barry and his colleague Professor Robin Warren (who both come from Western Australia) were researching stomach ulcers – big, painful sores on the lining of the inside of your stomach. For years, people believed that ulcers were caused by stress, spicy foods and too much acid in the stomach.
However, Barry and Robin had a different theory. They had found that the ulcers of their patients contained a tiny bacteria (a germ). They named the bacteria ‘Helicobacter pylori’ (let’s call it H. Pylori for short). They made a hypothesis that H. Pylori was getting into people’s stomache and causing the ulcers. To test the hypothesis, Barry did a very brave thing – he decided to infect himself with H. Pylori and see what happened. Sure enough, he developed a nasty ulcer!
Fortunately he and Professor Warren had also developed a treatment, so he was able to recover. They were also able to treat many other people with painful ulcers. This discovery completely changed the way that doctors all over the world could identify and treat stomach ulcers.
As a recognition of the important, revolutionary nature of their work, Professors Marshall and Warren were awarded the 2005 Nobel Prize in Physiology or Medicine – the highest prize a scientist can receive.