Inclusion Criteria1. Aneurysmal subarachnoid hemorrhage, Fisher Grade III.
2. Patient or spouse or first degree relative able to give informed consent
3. Age greater then 18
4. Aneurysm secured surgically, or via endovascular technique
5. Subject seen within 96 hours of bleeding
Exclusion Criteria1. Contraindication for the use of simvastatin
2. Hunt-Hess Grade V
3. Initial intracranial pressure over 30 cm H2O and sustained for more then 30 minutes
4. Patient already on an HMG CoA-reductase inhibitor.
5. Patients with severe chronic renal failure (creatinine >3 and/or BUN >40).