Incretin-based therapy is a novel approach to type 2 diabetes, and it is based on the fact that nutrient ingestion elicits from the intestinal secretion of GLP-1 and GIP (glucose-dependent insulinotropic peptide). These hormones, which rise postprandially, have effects on islet function to lower glucagon and raise insulin, both of which are very desirable for addressing the pathophysiology of type 2 diabetes. There are also other sites of action, including influences on gastric emptying, satiety, and -- potentially -- influences on glucose utilization in peripheral tissues. These therapies offer a unique opportunity to regulate glucagon secretion, which is generally perturbed in type 2 diabetes, and address in a broader sense the combined disorders of insulin secretion and impaired insulin action that characterize type 2 diabetes.