We will tell the volunteers that we are conducting this study in healthy volunteers to determine how amantadine is eliminated from the body. We will explain the pharmacology of amantadine and the potential side effects of a single dose before we obtain consent. Volunteers will be told of the potential for concurrent alcohol ingestion to result in the presence of acetylamantadine in urine. Volunteers will be required to abstain from alcohol consumption for at least one day prior to and including the time involved in the amantadine ingestion and urine collection. Any previous adverse reaction to amantadine will exclude a person from volunteering from this study. Subjects will be informed that side effects from this drug ingestion are highly unlikely because only a single dose will be administered. Any side effects if they occur will be related to the effect of amantadine on the brain. These effects may include insomnia, jitteriness, difficulty in concentrating and mental depression. However, these are the side effects associated with chronic ingestion of amantadine and are highly unlikely to occur with ingestion of a single dose. Once consent is obtained, the volunteers will ingest a therapeutic dose of amantadine (200 mg) in the morning, at least 2 hours before breakfast, and their complete urine will be collected over a period of 12 hours post dose. A previous clinical study in our laboratory with collections of urine for a total of 8 hours demonstrated that this collection time was sufficient to collect all metabolically produced acetylamantadine in the urine. The urine samples will also be analyzed for their content of creatinine as an indication of the completeness of the urine collection. The urines will then be labeled with a code and frozen at -20°C until analyzed. The urine will be analyzed for acetylamantidine by our established gas chromatography method. The technician analyzing the samples will not have access to any participant information other then the code on the label. Saliva specimens will also be collected at 2 hour intervals after amantadine ingestion. It should be noted that with the morning dose of amantadine collection of multiple saliva samples will be simplified and allow for the determination of the optimal time after dose for the urine analysis. Furthermore, this design will identify the window of opportunity to give the best signal to noise ratio for acetylamantidine production. Blood samples will be collected 1 hour prior to dosing and 2 hours post dose.