Changes in the types and concentrations of albumin-bound fatty acids in plasma have been related to subsequent changes in platelet and endothelial cell function both in vitro and in vivo. Fatty acids in the linoleate and linolenate sequences with the potential to act as prostaglandin and thromboxane precursors, seem to play a fundamental role in the homeostatic balance between platelets and endothelial cells. Variations in this balance may be directly related to the tendency to thrombosis.