Reactive hypoglycemia may result from a variety of causes and therapy often is not satisfactory Six patients with reactive hypoglycemia were treated with sulfonylurea agents. This therapy alleviated their symptoms, corrected their hypoglycemia, and restored their abnormal insulin responses to normal. The hypoglycemia in two of these patients appears to be related to alimentary factors, in three to diabetes mellitus, and in one patient to an isolated growth hormone deficiency.