Bipolar disorder is a chronic disease characterized by recurring episodes of mania and depression that can lead to disability. This study investigates the protective effects of edaravone (3-methyl-1-phenyl-2-pyrazolin-5-one), a drug with well-known antioxidant properties, in a model of mania induced by ketamine in rats. Locomotor activity was assessed in the open-field test. Superoxide dismutase (SOD), catalase (CAT) and thiobarbituric acid reactive substances (TBARS) levels were measured in order to evaluate oxidative damage in the rat hippocampus and prefrontal cortex. Increased locomotor activity (hyperlocomotion) was observed at the open-field test with ketamine treatment (25 mg/kg, i.p., 8 days). Edaravone (18 mg/kg) treatment did not prevent hyperlocomotion in the mania model induced with ketamine in rats, but lithium chloride (47.5 mg/kg, i.p., positive control) did prevent hyperlocomotion. Edaravone and lithium chloride treatments were found to reduce the increase in SOD and CAT activity following ketamine administration in a non-significant manner but caused no change in TBARS levels.