The effect of cavinton on the systemic (by the method of diluting Evans blue according to Stewart-Hamilton) and cerebral (by the method of rheoencephalography) hemodynamics was examined in 38 patients with chronic insufficiency of the cerebral circulation (CICC) in the presence of either atherosclerosis alone (n = 22) and its combination with arterial hypertension (n = 16). Cavinton decreased the peripheral vascular resistance and the tone of the small and median vessels of the brain, increased the cardiac output and improved the rheological properties of the blood (it lowered the globular volume, viscosity and hematocrit). The best results were attained with the parenteral administration of the drug. Indications for and contraindications to cavinton in patients with CICC are discussed.