It was long thought that gastric ulcers and other digestive woes were brought about by stress. But in 2005, clinical fellow Barry J. Marshall and pathologist J. Robin Warren were awarded the Nobel Prize in Physiology or Medicine for recognizing the role of Helicobacter pylori in gastritis and peptic ulcer disease. Now physicians can point their collective fingers at H. pylori when it comes to a host of gastric maladies in their patients.