We measured plasma levels of all the antioxidant-micronutrients in subjects with HIV infection and controls. Plasma levels of all the carotenoids, including lutein, cryptoxanthin, lycopene, alpha-carotene and beta-carotene as well as vitamins A, C and E and cholesterol were assayed in 35 subjects with HIV infection and 38 controls. We found a significant depletion of all the carotenoids (P < 0.001) and vitamin C (P < 0.01) and cholesterol (P < 0.001) but not vitamins A or E in HIV-infected subjects. Further analysis of the HIV-infected subjects revealed that plasma levels of 4 of the groups of carotenoids and cholesterol were correlated with CD4 count but that beta-carotene and vitamins A, C and E were not. These results are reviewed in the light of the published literature and we conclude that these abnormalities of antioxidant-micronutrients are likely to reflect a metabolic phenomenon associated with HIV infection. However, an additional contribution to these deficiencies from malabsorption later in HIV disease cannot be ruled out.