One of the most common symptoms is pain or discomfort in the upper abdomen. It is known that one in four people in the community have upper abdominal distress at times. This can be caused by a large number of medical conditions, including peptic ulcer disease, gallstones, esophageal inflammation (esophagitis), and very rarely cancer, to name the major conditions. However, there remain a large number of people who after being investigated have none of these medical conditions. Indeed, there is no obvious cause for their symptoms. Patients who have this type of dyspepsia are referred to as suffering from functional dyspepsia.