Inclusion Criteria:

• Patients who receive explanation on this study and give informed consent
• Patients aged 30 to 85 years
• Baseline NIHSS less than 15
• Onset of symptoms within 48 hours of the start of investigational product
• Full functional independence prior to the present stroke indicated by an mRS score of 0, 1, 2

Exclusion Criteria:

• Evidence from CT or MRI scan of an acute intracranial hemorrhage, a tumor, encephalitis or any diagnosis other than acute ischemic stroke likely to cause the present symptoms.
• Previous regular use of an antiplatelet agent or warfarin
• Patients with known cardiac disease likely to cause cardiogenic embolism or congestive heart failure
• Evidence from CT or MRI scan of midline shift when visiting hospital
• Uncontrolled hypertension (SBP>220 mmHg or DBP>120 mmHg)
• Hypotension (<90/60 mmHg)
• Patients with known bleeding diathesis or coagulation disorder
• Patients with liver disease (ALT>100 or AST>100), or renal disease (creatinine>2.0 mg/dl)
• Known severe anaemia (hemoglobin<8.0 mg/dl), or thrombocytopenia (platelet<100,000/mm3)
• Scheduled for endarterectomy within 3 months
• Severe co-morbidity likely to limit patient's life expectancy to less than 6 months
• Patients with alcohol or illegal drug abuse or dependency
• Pregnant or lactating patients. When administrating to females, it should be confirmed that the patients is in the menopause (by evaluation of investigators) or permanently infertile (hysterectomy or surgical operation like bilateral tubal ligation, bilateral oophorectomy, etc). If a patient is likely to be pregnant, the patient should not be pregnant before randomization. And, the patient should use reliable contraception between at least 3 weeks before randomization to 7 days after the final administration of study drug.
• Patients treated by thrombolytic agents like tPA after onset of stroke