Type 2 diabetes mellitus is characterized as a chronic disease.Distinctly available therapies have been manifested till date but, Dipeptidylpeptidase-4 (DPP-4) inhibitors are frequently used all over the world as bloodglucose lowering treatment for patients afflicted with type 2 diabetes mellitus.DPP-4 inhibitors span an interval of activity of incretin peptides: GLP-1 and GIP,which elicit glucose-dependent insulin secretion and inhibit glucagon secretion.Currently, oral hypoglycemic drugs (DPP-4 inhibitors) are being incorporated for thetreatment of T2DM. This evidence concerns the gene GLP1R and type 2 diabetes mellitus.