Propranolol on Post Stroke Immune Status and Infection

Inclusion Criteria: 1. Age: 60 years older and less than 90 years. 2. Onset of new neurological deficits within 24 hours at the time of randomization and propranolol treatment can be initiated within 24 hours of symptom onset. 3. Clinical signs consistent with the diagnosis of stroke, including impairment of language, motor function, cognition, and/or gaze, vision, or neglect. 4. Initial NIHSS score of 11 or greater or Total GCS score (aggregate of verbal, eye, and motor response scores) of 5 or greater and no more than 12 at time of enrollment. 5. MRI or CT scan confirmed stroke. 6. Inability to tolerate normal diet or fluids because of: a. impaired consciousness levels; b. failed clinical bedside swallowing assessment performed by a trained and qualified assessor; c. "nil orally" orders, nasogastric tubes, modified diet or requiring compensatory feeding techniques. 7. TOAST: Large-artery atherosclerosis. 8. Signed and dated informed consent by the subject, legally authorized representative, or surrogate obtained. Exclusion Criteria: 1. Time of symptom onset that cannot be reliably assessed. 2. Subjects considered as candidates for immediate surgical intervention by the neurosurgery service. 3. Pregnancy or parturition within previous 30 days or active lactation. 4. Coagulation disorders (platelet count less than 50x109/L, elevated baseline APTT or INR\>1.3) or use of anti-coagulant drugs within the last 24 hours. 5. Use of beta blockers (propranolol, metoprolol, sotalol, carvedilol, bisoprolol, atenolol, esmolol) or antibiotics within 30 days. 6. Use of reserpine within the last 30 days. 7. Pre-stroke dementia or disability. 8. Admission with any of following signs: 1). Fever\>38℃; 2). Signs of pneumonia in chest CT scan; 3). White blood cell count\>12000 or \<4000 /μL; 4). Cough, sputum or dyspnea; 5). Respiratory rate\>25. 9. Severe liver, kidney disease, or malignancy, life expectancy is less than 14 days. 10. Bronchial asthma or COPD. 11. Cardiogenic shock. 12. Severe or acute heart failure. 13. Degree II-III atrioventricular block. 14. Sinus bradycardia (heart rate ≤75/min). 15. Known anergic to propranolol or amoxicillin. 16. Current participation in other interventional clinical trials. 17. Immunosuppressant therapy or known immunosuppression. 18. Inability to undergo neuroimaging with magnetic resonance.