It has been reported that α-tocopherol, an antioxidant agent, may play a role in preventing diabetic angiopathy. However, there is little evidence to show the effect of α-tocopherol on the production of pro-inflammatory cytokines in endothelial cells. Therefore, we examined the effect of α-tocopherol on the regulation of IL-8 synthesis induced by high glucose and/or thrombin in endothelial cells. Thrombin alone markedly increased the IL-8 release. Furthermore, high glucose levels and thrombin combined had additive effects on IL-8 synthesis, and α-tocopherol diminished their effect; α-tocopherol also inhibited the phosphorylation of IκB-α induced by high glucose levels and/or thrombin. Our results suggest that the administration of α-tocopherol to diabetic patients may have a beneficial effect for the prevention of diabetic vascular complications by the inhibition of IL-8 synthesis from endothelial cells.