The activities of the blood kallikrein-kinin system components (plasma kallikrein, alpha 1-antitrypsin, alpha 2-macroglobulin), and gonadotropin levels in various phases of the menstrual cycle were measured in 35 women ob various age groups. The same parameters were investigated in 28 women with dysfunctional uterine bleedings of the climacteric period. Phasic changes in the blood kallikrein-kinin system components, closely related to the hormonal status, were revealed over the course of the onto-genesis. Climacteric dysfunctional uterine bleedings were found associated with an elevated activity of the plasma kallikrein, parallelled by a relative insufficiency of the blood plasma inhibitor potential. A relationship between the activities of the blood kallikrein-kinin system components and endometrial function has been revealed. These findings necessitate search for approaches to pharmacologic regulation of the blood kallikrein-kinin system activity and to pathogenetic therapy of the climacteric dysfunctional uterine bleedings.