Peptic ulcer disease (PUD) involves the stomach or duodenum and is a significant cause of morbidity and mortality both in the United States and worldwide, with a lifetime prevalence estimated at 5–15%. For a good part of the 20th century PUD was felt to be a condition related to stress and dietary factors. More recently, our understanding of PUD has been advanced by research into the role of gastric acid secretion and the benefits of various classes of antisecretory medications and, perhaps most importantly, in 1984, by Warren and Marshall, who identified Helicobacter pylori (H. pylori) as a pathogenic agent in this disease. Proton pump inhibitor (PPI) therapy and H. pylori eradication regimens have altered the natural history of what once was a chronic disease, and they have also reduced peptic ulcer complications, limiting the need for surgery.