It has been reported that some modified low-density lipoproteins (LDLs) such as glycated LDL and malondialdehyde-rich LDL (MDA-LDL) probably exist in the circulation. The present study was undertaken to investigate the in vitro and in vivo metabolism of MDA-LDL occurring in chronic haemodialysis patients and the effects of alpha-tocopherol on these abnormalities. MDA-LDL from haemodialysis patients was degraded more rapidly by human monocyte-derived macrophages and disappeared more slowly from the circulation when compared with LDL from healthy controls. Treatment with alpha-tocopherol at doses of 600 mg/day for 2 weeks resulted in improvement of these metabolic abnormalities depending upon the degree of return to normal MDA concentrations in LDL.