Patients between 18 and 80 years of age who have had a mild or moderate acute stroke between 3 and 24 hours before starting study drugs may be eligible for this study. Candidates will be screened with a medical history and physical examination, blood tests, rating of neurological deficits such as cognition deficits or problems walking that resulted from the stroke, and a computed tomography (CT) scan of the head. CT involves the use of specialized X-rays to obtain images of the brain. The patient lies on a table that is moved into a cylindrical machine (the scanner) for the imaging study, which usually takes about 5 to 10 minutes.