DESPITE its apparent infrequency, acute retrograde jejunogastric intussusception is a serious complication of gastroenterostomy unless recognized promptly and treated surgically. The first gastroenterostomy was performed in 1881, but it was not until 1917 that the first complication of this type was recorded by Steber.1 Bettman and Baldwin2 collected 33 cases in their comprehensive review of the subject in 1933, and since that time 17 additional cases have been reported. The following report of a typical case illustrates the necessity of early recognition of this condition. REPORT OF A CASE Z. P., a 55 year old white man, was admitted to the hospital on Sept. 26, 1947, with the chief complaint of severe pain in the upper abdominal region and vomiting. His first admission was in 1936, when a diagnosis of duodenal ulcer was made. Subsequently, his symptoms of gnawing epigastric pain, relieved by food, became progressively worse until