To evaluate the efficacy and safety of neyromidin in the treatment of Stage I hypertensive dyscirculatory encephalopathy (HDE) and to analyze long-term treatment results.Fifty-seven with Stage I dyscirculatory encephalopathy in the presence of grades 1-2 arterial hypertension were examined. Clinical, psychological, and electrophysiological studies were performed and the efficacy of neyromidin was evaluated using the SANDOS geriatric scale. Neyromidin as monotherapy was used as one tablet (20 mg) b.i.d. during a meal. The duration of course treatment was 3 months.Positive changes in the early manifestations of HDE were observed just on day 45 of therapy. The therapeutic effect of the drug manifested as a reduction in the degree of clinical symptoms. There were positive changes in attention, memory, kinetics, verbal associations, counting. The most noticeable improvement was seen in the values of memory and intellectual processes, suggesting higher working capacity, reduced fatigability, and eliminated sluggishness of intellectual processes. EEG displayed a higher amplitude level, a better response to rhythmic photostimulation, and a total power rise in a- and 8-ranges, which was indicative of the activated effect of neyromidin on the functional state of brain structures.Neyromidin (20 mg b.i.d. for 3 months) was shown to be effective and well tolerated. The drug reduced the magnitude of clinical manifestations and improved psychological functions and electrophysiological parameters.