This is a randomized, double blind, placebo-controlled, parallel, multicenter research in order to evaluate the effect of Shuxuetong injection in prevention of symptomatic or asymptomatic new cerebral infarction within 10 days.

Subgroup study：Evaluate the role of advanced diagnostic technique in identifying potential causes of Embolic Stroke of Undetermined Source (ESUS).

Shuxuetong injection or Placebo injection for 10days. About 2416 patients randomized at 80 centers all over China with 20 subgroup study centers.

Face to face interview at baseline, 10 days, and 90 days.

Inclusion criteria

1. More than or equal to 18 years old and less than 80 years old;
2. Acute ischemic stroke, brain magnetic resonance imaging showed non lacunar infarction (subcortical infarction less than or equal to 1.5 cm);
3. Onset within 72 hours;
4. Patients or their family members are willing to sign the informed consent.

Exclusion criteria

1. Intracranial hemorrhage: cerebral hemorrhage, subarachnoid hemorrhage, etc.;
2. Transient ischemic attack;
3. Lacunar infarction;
4. History of acute stroke within 6 months;
5. Clear diagnosis of other causes of ischemic stroke (arterial dissection, arteritis, vasospasm, etc.);
6. The acute infarcts lesion more than one-half lobe in size;
7. Preceding modified Rankin Scale (mRS) score ≥ 2;
8. Cumulative usage of traditional Chinese medicine which activating blood circulation more than 3 times after onset, including but not limited to: Danhong, Xueshuantong, Xuesaitong, Ginkgo biloba, sodium ozagrel, Salvia miltiorrhiza, ligustrazine, Erigeron breviscapus, etc;
9. Chronic liver disease, liver and kidney dysfunction, lifted alanine aminotransferase (>3 times the ULN), lifted serum creatinine (>2 times the ULN）;
10. History of coagulopathy, systemic bleeding, thrombocytopenia or neutropenia;
11. Blood pressure >90/60 mmHg or ≤220/120 mmHg after treatment;
12. Serious heart or lung disease, in the judgment of clinical study staff, would not suitable to participant in the trial;
13. Patients with atrial fibrillation who were scheduled or likely to receive anticoagulant therapy with unfractionated heparin or low molecular weight heparin within 2 weeks after randomization
14. A medical condition likely to limit survival to less than three months or any other condition judged by the clinic team to likely limit the adherence to study procedures;
15. Known allergies for ingredients of the drug, allergy history for food or drug;
16. Pregnant, currently trying to become pregnant, or of child-bearing potential and not using birth control;
17. Participation in another clinical trial within 30 days;
18. Unable to understand and/or comply with the study procedures and/or follow-up studies due to mental illness, cognitive or emotional disorders.

Subgroup Exclusion Criteria

1. History of atrial fibrillation
2. Atrial fibrillation in 12-lead electrocardiogram (ECG);
3. Heart rate monitoring (dynamic electrocardiogram telemetry) up to 20 hours or more detected atrial fibrillation for 6 minutes or more;
4. Intracardiac thrombosis in thoracic or esophageal echocardiography;
5. Occlusion or proximal vessel infarction for more than 50%.