Clinical Assessment Assessments will be done at baseline and at the end of one, two, three and four weeks during administration of drug and eight and twelve weeks after initiation of the trial. Patients will be asked to come to the clinic at approximately the same time of day for each infusion. The assessments will be done each Friday throughout the trial, once prior to the infusion of the glutathione/placebo and again one hour after the infusion. The following assessments will be done: Unified Parkinson's Disease Rating Scale, timed walking test, tapping test and clinical global assessment by both the physician and the patient. Patient diaries and the Parkinson's Disease Questionnaire, a quality of life measurement, will be done weekly. Patients will also be videotaped using a standard protocol. The treating physician will not be doing the assessments, all assessments will be done by a blinded investigator. Assessment forms can be found in the appendix.