Up until the 1980s, gastroenterologists believed stomach ulcers, a debilitating (and sometimes deadly) ailment that affected up to 10 percent of people, were caused by stress. Australian internist Barry Marshall believed differently; he thought they were caused by a bacteria called Helicobacter pylori.
“Unable to make his case in studies with lab mice (because H. pylori affects only primates) and prohibited from experimenting on people, Marshall grew desperate,” Discover reported in a 2010 article. “Finally he ran an experiment on the only human patient he could ethically recruit: himself. He took some H. pylori from the gut of an ailing patient, stirred it into a broth, and drank it.”
He developed gastritis, began vomiting, became sick and exhausted and had breath that could kill a