Inclusion Criteria- Patients have type 2 diabetes mellitus (30 or more years old and 85 years old or less).
- Patients give their informed consent to participate.
Exclusion Criteria- Patient has electrocardiographic changes, including ischemic ST-segment depression, ST-segment elevation, or pathologic Q waves.
- Patient has fixed ischemic heart disease, utilizing coronary angiography.
- Patient has cerebral vascular disease, including cerebral infarction, past hemorrhage, and experience of transient ischemic attack.
- Patient has arteriosclerotic disease, which needs internal medicine and/or surgical medical treatment.
- Patient has already taken the following anti-platelet or anti-thrombotic medicine: aspirin, ticlopidine, cilostazol, dipyridamole, trapidil, warfarin, and argatroban.
- Patient has severe gastric and/or duodenal ulcer.
- Patient has severe liver dysfunction.
- Patient has severe renal dysfunction.
- Patient has allergy for aspirin.
- Patient has atrial fibrillation.
- Pregnancy or the possible case of pregnancy.