The effect of oral administration of buspirone (0.5-1.0 and 2.0 mg/Kg) on GSH levels was studied in rat liver. The modulating activity of buspirone on hepatic content of this tripeptide is clearly opposite to that of DAZ, put into evidence by us in previous works. Thus our observations let us hypothesize a different mechanism of action for buspirone than that for benzodiazepines.