We have studied the effects of oral vitamin E (vE) on serum vitamin A (vA) levels and vA transport proteins, retinol binding protein (RBP) and prealbumin (PA), in normal subjects taking and not taking pharmacological doses of vA and/or vE acetate. Nineteen subjects were given 9009 ug of oral vA acetate daily for one week. Ten of these continued on 9009 ug of vA daily for two weeks (group I), while nine received 147 mg of vE acetate in addition to vA (group II). A third group (group III) consisted of 10 subjects who received only 147 mg of vE daily for 3 weeks. Group IV represented control subjects not given either vA or vE pills over the 3 week study period. Groups I and II showed significant increases in serum vA levels after 1 week of vA treatment. Group I to week 3 (p<0.01) while group II serum vA levels significantly fell from week 1 to week 3 (p<0.01). No significant differences were demonstrated in RBP or PA in groups I and II. Group III showed a significant fall in serum vA and RBP levels from initial to week 3 (p<0.005) with no significant change in PA. Control subjects (group IV) showed no significant variation of any parameter over the three week test period. The fall in serum vA and RBP seen among our subjects taking vE alone is consistent with either enhanced hepatic vA uptake or increased vA transport to and utilization by peripheral tissues.