Background. The search for the harmless and effective methods for the drug-free correction of various vegetovascular manifestations associated with the climacteric syndrome (CS) is currently a serious challenge facing modern medicine. Dysfunction of the ovaries during the perimenopause is characterized by the impaired production of sex steroids. The estrogens and progesterone, in their turn, are able to interact with macrophages via the specific receptors of steroid hormones localized on the surface of these cells. In this context, the trans-cranial electrical stimulation (TES) technique is of great interest due to its strong influence on the functional state of the central nervous system, subcortical brain structures, the vegetative and hormonal balance. The immunotropic effects of TES therapy described in the literature provide a basis for anticipating its beneficial action on the functional activity of monocytes/macrophages in the women presenting with the climacteric syndrome. Aims — the objective of the present study was to evaluate the influence of trans-cranial electrical stimulation on the state and stability of lysosomal membranes of blood monocytes and peritoneal macrophages, the secretory and synthetic activity of these cells in the women exhibiting the vegetovascular manifestations of the climacteric syndrome. Materials and methods. The influence of the transcranial electrical stimulation (TES) technique on the stability of lysosomal membranes of blood monocytes and peritoneal macrophages, the secretory and synthetic activity of these cells was studied in 23 women at the age from 45 to 52 years presenting with vegetovascular manifestations of the climacteric syndrome. The control group was comprised of 16 healthy women of the same age. The state of blood monocytes and peritoneal macrophages was evaluated before and after the course of TES therapy. To determine stability of lysosomal membranes of blood monocytes and peritoneal macrophages and calculate the stability index (PSI), the isolated cells were cultured in a medium 199 supplemented by sterile 0.5% L-glutamine and 2.5% mixed human serum previously heated at 560 °C for 30 min and at 37 °C for 12–15 hours. The micro-method was employed to determine secreted lysozyme (Lsec) as well as total lysozyme (L total=L secreted plus L intracellular) following 4–6-fold freeze-thawing of the cultured cells. The data obtained on the levels of secreted and total lysozymes were used to calculate PSI by the formula: PSI=Lsec/Ltotal´100%. The increase in PSI above the optimal value (53– 58%) was regarded as giving evidence of labilization of the lysosomal membranes and the decrease of this parameter as the indicator of membrane stabilization. Based on the difference between the total lysozyme levels before and after cultivation, the amount of newly synthesized lysozyme (L int) was determined. Results. The results of the present study give evidence that the women with climacteric syndrome experience labilization of the blood monocytes and peritoneal macrophages; their lysozyme secretion increases while its synthesis decreases. In other words, the therapeutic application of the transcranial electrical stimulation technique contributed to the disappearance or reduction of «hot flashes» and the change of these features to the level characteristic of the healthy women. Conclusions. The data obtained extend our knowledge about the mechanisms underlying the action of TES therapy on the macrophagic cells; moreover, they allow to draw the conclusion that the course of medication with the application this technique not only decreases the intensity of manifestations of the climacteric syndrome but also corrects the function of the immune system during the perimenopause.