As explained in this New York Times article, Dr. Barry J. Marshall and Dr. J. Robin Warren won the Nobel Prize for Physiology or Medicine today. They discovered H. pylori, a bacterium that causes stomach inflammation, ulcers, and cancer. To prove the theory, Dr. Marshall conducted an experiment on himself.
"He swallowed a gastroscope tube to allow another doctor to look at his stomach and take several biopsies. These procedures and examinations were needed to document that Dr. Marshall had no H. pylori in his stomach and did not suffer from gastritis or another abnormality.
Dr. Marshall waited 10 days for the areas that had been biopsied to heal and then swallowed a pure culture of H. pylori. A week later, he had an unusual sensation of fullness after eating supper and felt ill. Friends told him that his breath was "putrid."
Ten days after the onset of symptoms, Dr. Marshall underwent the first of an additional three gastroscopies. Biopsies obtained through them showed that he had developed gastritis or inflammation of the stomach, but he did not continue the experiment long enough to develop an ulcer. His symptoms quickly disappeared after treatment."