Rheological and hydrodynamic properties of blood taken from patients with stable angina pectoris were investigated in different periods (1, 7 and 28 days) of combined treatment (calcium antagonists, nitrates, beta-blockers, aspirin). The high viscosity syndrome (elevated blood viscosity, red cell aggregation, hyperfibrinogenemia) was registered before treatment, 1, 7 and 28 days after beginning of the treatment. Low hydrodynamic index (the speed of blood flow in turbulent regimen) reflected insufficiency of endogenic antiturbulent factor in the blood. The addition of high-molecular-weight polyethylene oxide to blood samples in concentration 2 x 10(-6) promoted normalization of the hydrodynamic index and decline of red cell hyperaggregation.