One hundred and twelve patients with diabetes mellitus type I (DMTI) with different severity and compensation state of the disease were examined. A comparison group included 40 patients with discirculatory encephalopathy (DE). Patients with DMTI and DE were randomized to basic therapy (treatment of glycemia, vasoactive drugs) and treatment with glycine (0,1g) and limontar (0,25g) 3 times a day. All patients underwent the complex examination including the assessment of neurological and neuropsychological status, the endocrinology clinical-laboratory study, ultrasonic dopplerography of head and neck vessels and transcranial dopplerography with vascular reactivity tests (response to nitroglycerin); direct ophtalmoscopy, the study of plate-let homeostasis. Efficacy and safety of treatment were assessed after 3 months. The dynamics of neurological and neuropsychological status, vascular reactivity results (the increase of number of patients with the adequate response to nitroglycerin), platelet aggregation (the reduction of aggregate size and aggregation velocity), microcirculation disorders (the increase of number of patients with non-proliferative retinopathy and the decrease of those with preproliferative one) were significantly better in the group treated with glycine and limontar. The treatment effect was higher in DMTI patients with encephalopathy that was likely explained by the greater role of microcirculation mechanisms in the formation of encephalopathy in patients with diabetes mellitus.