Persons with diabetes mellitus often have disordered gastrointestinal function, usually attributed to autonomic neuropathy. Hypoglycemia in persons taking insulin has been considered a possible result of anorexia and gastric atony, but not a potential cause of gastrointestinal symptoms. Three patients with diabetes developing before age 30 yr and of long duration had severe gastrointestinal complaints for 1-9 mo, with symptoms suggesting nocturnal hypoglycemia. All recovered rapidly with no specific treatment other than reduction of insulin doses. Studies identified no gastrointestinal pathology. These patients may represent a subgroup of persons with diabetic enteropathy, in whom recurrent hypoglycemia provokes a reversible derangement of gut function with accompanying symptoms.