If the type 2 diabetes is left untreated, it can eventually be lead to vascular complications, including nephropathy, retinopathy, neuropathy, coronary heart disease, and CVA. The current antidiabetic drugs are all generally effective in the medium term, not effective eventually. In addition, they may also be associated with an increased risk of hypoglycemia, weight gain, and gastrointestinal intolerance. The dipeptidyl peptidase 4 (DPP-4) inhibitors control elevated blood glucose by increasing active glucagon- like peptide-1 (GLP-1), increasing insulin secretion and inhibiting glucagon secretion. The DPP-4 inhibitors, such as vildagliptin (Galvus) and sitagliptin (Januvia), have shown clinically significant HbA1c reductions up to 2 years of treatment and many potential advantages including a low risk of hypoglycemia, but no effect on body weight. They are used as monotherapy and also in combination with metformin or thiazolidinedione or sulfonylureas and are suitable for once-daily oral dosing to treat patients with the type 2 diabetes mellitus. The thiazolidinediones are agonists for peroxisome proliferator-activated receptor γ (PPAR-γ) and lowering blood glucose primarily by increasing insulin sensitivity in peripheral tissues. Rosiglitazone is widely used as monotherapy or in fixed dose combinations with either metformin or glimepiride to treat patients with the type 2 diabetes mellitus, but its effect on cardiovascular morbidity and mortality has not been determined. Dr. Nissen assisted that rosiglitazone should be associated with a significant increase in the risk of myocardial infarction. This review focused on the clinical effect of DPP-4 inhibitors and the relations between rosiglitazone and the risk of myocardial infarction.