We compared CSF and serum levels, and the CST/serum ratio of alpha-tocopherol (vitamin E), measured by HPLC, in 44 apparently well-nourished patients with Alzheimer's disease (AD) and 37 matched controls. CSF and serum vitamin E levels were correlated, both in AD patients and in controls. The mean CSF and serum vitamin E levels were significantly lower in AD patients, and the CSF/serum ratio of AD patients did not differ significantly between the 2 study groups. CSF vitamin E levels did not correlate with age, age at onset, duration of the disease and score of the Minimental State Examination in the AD group. Weight and body mass index were significantly lower in AD patients than in controls. These results suggest that low CSF and serum vitamin E concentrations in AD patients could be related with a deficiency of dietary intake of vitamin E.