While the word ulcer can refer to any type of sore or lesion that won't heal, in common usage it typically refers to peptic ulcers, very painful lesions that form in the stomach or intestine. For years, even centuries, they were believed to be caused by stress and/or particular kinds of food and were considered a chronic condition. That is, it was thought that people couldn't "cure" this condition, they just just had to manage it with antacids, diet — eating only bland food, for example — and lowering stress levels. The classical stereotype of the overworked Type-A manager would depict him getting off the phone and reaching for antacids as he clutched his midsection, with the idea that stress was making him ill.
Because the stomach is a highly acidic environment, it was thought that bacteria simply couldn't live there for long. In 1982, however, Robin Warren, an Australian pathologist, proved that patients with chronic ulcers also had colonies of bacteria inhabiting their stomach. Barry Marshall, of the University of Western Australia, took this finding and, working with Warren, located and identified the bacterium in question, which they named Helicobacter pylori.
Their findings were so contradictory to prevailing conventional wisdom that their work got very little notice, even though it promised a permanent cure to this condition. In a dramatic display of the validity of their findings, Dr. Marshall deliberately infected himself with Helicobacter pylori and gave himself ulcers, which were then cured by a round of antibiotic treatment. Still, it took the next two decades to overthrow long-held beliefs on the treatment of this problem, and many laymen today still believe that it is chronic and incurable. In October 2005, Warren and Marshall were awarded the Nobel Prize in medicine, in recognition for their groundbreaking work.