Phagocytic activity of blood cells and free fatty acids content in rat brain were studied during experimental disturbances of blood supply. It is shown that disturbances of cerebral circulation in rats lead to a depression of a phagocytic part of immunity though during the expressed damage during the early periods its intensification is observed. During disturbances in brain circulation, the most significant changes are seeing in the contents of arachidonic and palmitic fatty acids. The level of changes in fatty acids contents and their dynamics depended on the degree of circulatory disturbances. Correlation communications between activity of phagocyte blood cells and changes in fatty acid content in rat brain during circulatory alterations point to the certain dependence on systemic oxidative stress.