The aim of the present study is to evaluate the efficacy of miglitol alone and in combination with sitagliptin on changes in blood glucose levels, precisely evaluated by a continuous glucose-monitoring system (CGMS) [21-23], and determine the effect of these agents on changes in insulin, 1,5-anhydroglucitol (1,5 AG), glucagon, GLP-1, and GIP levels in subjects with type 2 diabetes. The gene discussed is GCG; the disease is type 2 diabetes mellitus.