1. Using deuterium-labelled alpha-tocopherol (vitamin E), the plasma kinetics of alpha-tocopherol derived from supplemental RRR-alpha-tocopherol and RRR-alpha-tocopheryl acetate were determined in asymptomatic individuals who smoke and, for comparison, in a group of healthy non-smokers. 2. Venous blood samples were withdrawn 6, 12 and 27 h after the oral administration of a gelatin capsule containing an equimolar mixture of RRR-alpha-tocopheraol and RRR-alpha-tocopheryl acetate. Plasma concentrations of endogenous and administered forms of alpha-tocopherol were determined by a combination of HPLC and GC-MS. 3. Both the free phenol and the acetate ester concentrations of alpha-tocopherol were lower in smokers than in non-smokers: 0.99 versus 1.60 (P < 0.05) and 0.66 versus 1.49 (P < 0.05) mumol/mmol cholesterol for RRR-alpha-tocopherol and RRR-alpha-tocopheryl acetate respectively. The highest concentation of alpha-tocopherol derived from administered RRR-alpha-tocopherol and its acetate ester were observed in plasma at 12 h (compared with 6-h and 27-h measurements) in most subjects. 4. Although the two forms of alpha-tocopherol were administered in equal doses, plasma from smokers contained significantly higher concentrations of RRR-alpha-tocopherol derived from the free phenol form than from the acetate form (0.99 versus 0.66 mumol/mmol cholesterol, P < 0.05, 12 h). Non-smokers did not exhibit preferential uptake of either form of vitamin E. 5. These results suggest that individuals who smoke have either a reduced ability to absorb alpha-tocopherol, particularly when it is presented as the acetate ester, or increased clearance of newly absorbed alpha-tocopherol compared with non-smokers.