The effects of reduced glutathione (GSH) administration (1.2 g/day and 2.4 g/day intravenously) on erythrocyte glutathione levels, serum gamma-glutamyl transpeptidase activity (GGTP) and urinary glucaric acid elimination were studied in a population of 24 chronic alcoholics voluntarily admitted to a 30 day detoxification protocol in comparison to a 12 patient control group treated only with chlordiazepoxide (initial dose 75-100 mg/day). Glutathione treatment increases dose-dependently and in a significant way erythrocyte glutathione levels and hastens the recovery of serum GGTP and urinary glucaric acid elimination. The relationship between glutathione, GGTP and glucaric acid is discussed, suggesting the possible role of GSH against the oxidative damage of alcohol.