Gallic acid has been identified as an antioxidant component of the edible and medicinal plant Peltiphyllum peltatum. The present study examined its potential protective role against sodium fluoride (NaF)-induced oxidative stress in rat erythrocytes. Oxidative stress was induced by NaF administration through drinking water (1030.675 mg m(-3) for one week). Gallic acid at 10 mg kg(-1) and 20 mg kg(-1) and vitamin C for positive controls (10 mg kg(-1)) were administered daily intraperitoneally for one week prior to NaF administration. Thiobarbituric acid reactive substances, antioxidant enzyme activities (superoxide dismutase and catalase), and the level of reduced glutathione were evaluated in rat erythrocytes. Lipid peroxidation in NaF-exposed rats significantly increased (by 88.8%) when compared to the control group (p<0.05). Pre-treatment with gallic acid suppressed lipid peroxidation in erythrocytes in a dose-dependent manner. Catalase and superoxide dismutase enzyme activities and glutathione levels were reduced by NaF intoxication by 54.4%, 63.69%, and 42% (p<0.001; vs. untreated control group), respectively. Pre-treatment with gallic acid or vitamin C significantly attenuated the deleterious effects. Gallic acid isolated from Peltiphyllum peltatum and vitamin C mitigated the NaF-induced oxidative stress in rat erythrocytes.