The authors report on treatment of 55 patients with chronic circulatory insufficiency with the aid of vasodilators: sodium nitroprusside, nitroglycerine by intravenous drip, nitrosorbide per os, 30 +/- 2.3 mg 4 times daily, nitroglycerine ointment applied on the skin (dose: 1.7 +/- 0.1 inches, 4 times daily). All the drugs reduced venous tone, enhanced venous volume and limited return of the blood to the heart, decreased overfilling of the vessels of the lesser circuit and decreased diastolic filling of the left ventricle. This effect was accompanied by the unloading of the lesser circuit, diminishing of the size of the heart and utilisation of oxygen by the myocardium. Besides nitroglycerine exerts weak and sodium nitroprusside marked arteriolodilating action which is manifested in decrease of arterial pressure and resistance to voiding of the left ventricle. This action is accompanied with further decrease of cardiac dimensions, decrease of oxygen utilization and enhancement of indices of left ventricular haemodynamics. In 22 patients a combined treatment was undertaken with inotropic (digoxin) and vasodilating (sodium nitroprusside, nitrosorbid) drugs. It is shown that with increased end-diastolic volume of the left ventricle over 260 cm3 digoxin is ineffective haemodynamically and often leads to rhythm disorders. The use in such cases of sodium nitroprusside permits one to decrease the heart volume, restore its sensitivity to digoxin and the combination of these drugs, rather than their use separately, helps to combat circulatory insufficiency.