Little is known about the role of antioxidant activity in the pathogenesis of stroke-associated neuronal damage and impairment following a stroke. Increased free radical formation together with reduced antioxidant defense may increase neuronal injury. A low concentration of antioxidants such as alpha-tocopherol may influence the development of post-stroke dementia. The aim of this study was to evaluate the level of alpha-tocopherol and susceptibility of LDL to oxidation in a group of patients with dementia in comparison to controls. In a group of 68 patients with dementia, according to DSM-IV criteria, 42 with vascular dementia (VaD), 26 with Alzheimer type of dementia (AD) and 46 age-matched persons, with no signs of cognitive disorders (control group), we measured lipids, alpha-tocopherol and the kinetics of LDL oxidation. The levels of triglycerides (TG) and low-density lipoprotein (LDL) were significantly lower in patients with VaD in comparison to AD patients, but the atherogenic index was similar in both groups. alpha-Tocopherol was significantly lower in patients with VaD in comparison to patients with AD and controls: 9.9, 12.6 and 12.6 ng/ml, respectively, p<0.0001. Susceptibility of LDL to oxidation, measured by duration of lag phase did not reveal statistically significant differences between the groups. In patients with VaD, low levels of plasma alpha-tocopherol were observed, which indicate a reduced antioxidant defense in these subjects.