This study defines a modification of antioxidant systems by percutaneous absorption of fluocinolone acetonide. Total antioxidant status (TAS) provides an overall indication of antioxidant status. Superoxide dismutase (SOD), a primary antioxidant, accelerates the dismutation of the toxic superoxide radical produced during the oxidative energy processes into the less harmful molecules, hydrogen peroxide and molecular oxygen. We monitored the level of SOD and TAS in 7 males with psoriasis and 6 control subjects before and after a single application of fluocinolone acetonide 0.025% ointment to 90% of the body. The results showed that the plasma level of TAS was significantly increased (p < 0.02) at 24 h posttreat-ment. The erythrocytic level of SOD was significantly decreased (p < 0.01) only at 12 h after glucocorticosteroid application. The level of TAS and SOD in patients with psoriasis was also significantly increased (p < 0.01 for both situations) as compared to healthy controls. Our study suggests that fluocinolone acetonide as a therapeutic agent may play a role in the oxidative stress in skin diseases.