After obtaining informed consent, human participants will receive 500 mg/day of Setria® Glutathione or placebo for 120 days. Peripheral blood mononuclear cells (PBMC), neutrophils and serum will be obtained from blood draws before and after the 120 days. A daily diary of illness will be kept by each participant and will record any incidence of illness, the number of symptoms per incidence, and the number of days in which symptoms are present. This study is powered on the basis that over 120 days, the glutathione-supplemented group would experience 3% more healthy days compared to the placebo group. The analysis indicated 60 people per group. Timeline should be between mid-January to May because the Center for Disease Control and Prevention indicates that this is the cold and flu season (http://www.cdc.gov/flu/weekly/fluactivity.htm) in the southwest part of the country.