Abstract A sensitive and rapid reversed-phase HPLC method with electrochemical detection was developed for the analysis of glutathione in pharmaceutical preparations. The separation was achieved on an LC 18-DB (100×4.6 mm I.D.; 5 μm particle size) column. The mobile phase consisted of 0.1% (v/v) trifluoroacetic acid and acetonitrile (98:2, v/v). The effluent was monitored with dual electrochemical detection (applied potentials: E 1=+0.450 V; E 2=+0.750 V) in order to check simultaneously the declared amount of reduced glutathione and to quantify the related impurity oxidized glutathione. Limits of detection of 0.60 and 0.15 ng were achieved for the reduced and oxidized form, respectively. The method was validated and applied to the analysis of five commercial preparations containing reduced glutathione.