The association of progressive and recurrent peptic ulceration with non-insulin-producing islet-cell tumors of the pancreas was first observed by Zollinger and Ellison in 1955.1 In 19562 Ellison reviewed 24 cases of ulcerogenic tumors of the pancreatic islets from various sources and characterized this new clinical syndrome. It consisted of a hypersecretion of gastric juice with progressive peptic ulceration, recurring despite adequate medical and surgical therapy, and the presence of non-insulin-producing islet-cell tumors of the pancreas. The ulcers were frequently located in atypical sites, such as the jejunum and distal duodenum, as well as the esophagus, stomach, and duodenal bulb. Symptoms were usually referable to the ulcer and its complications and frequently resulted in death. The majority of these islet-cell tumors were considered malignant and in most instances consisted of cells devoid of beta granules, suggesting that they might be of alpha-cell origin. Since glucagon, or hyperglycemic-glycogenolytic factor, is