Determination of the slow isoenzymes of carbon esterases (SICE) in the urine by the disc-electrophoresis techniques was used as a marker of kidney impairment in 90 patients with II stage essential hypertension. In obsidan and visken treatment the frequency of SICE detection in the urine has increased from 30-50 to 70-100 per cent; the effective renal blood flow was reduced and specific peripheral resistance was increased and leg blood flow deteriorated. Subsequent administration of trental. phentolamine and corinfar alleviated the unfavourable effect of beta-adrenoblockers, enhanced renal blood flow, decreased the frequency of SICE detection to the initial level and improved the results of treatment.