We measured vitamin E and beta-carotene in the serum and in circulating lipoproteins in a large population of 15 patients with familial hypercholesterolaemia who were undergoing long-term treatment by low density lipoprotein (LDL) apheresis. The technique used for apheresis was dextran sulphate cellulose adsorption. The results showed that before LDL apheresis, patients had high vitamin E and normal beta-carotene levels in the serum and in the VLDL+LDL fraction. There were no relationships between serum levels of vitamin E and beta-carotene and the duration of LDL-apheresis. Low vitamin E and beta-carotene levels in the HDL fraction could be related to the low HDL concentrations in these patients. Vitamin E/cholesterol ratios were similar to those of the normolipaemic controls whereas beta-carotene/cholesterol ratios were lower. After LDL-apheresis treatment, the ratios in the HDL fraction fell whereas the ratios in the serum and in the VLDL and LDL fraction did not change. This study shows that these patients exhibited no deficiency in either serum of VLDL-LDL of vitamin E or beta-carotene after long-term treatment by LDL-apheresis and that the status of these antioxidants in serum was independent of the duration of treatment.