The effects of 10% hydroxyethylstarch solution on the cerebral microcirculatory bed and the blood-brain barrier were studied in Wistar rats during the acute period of severe brain injury. Positive changes in the morphometric values of the cerebral capillaries were observed in animals receiving intravenous injections of the drug, which promoted reduction of vascular permeability and cerebral tissue edema. These results confirmed the efficiency of hydroxyethylstarch as a component of infusion therapy in patients with severe brain injury.