In experiments on mice, we studied the analgesic activity of some 3-substituted derivatives of 1,4-benzodiazepines, including 3-propoxy-7-bromo-5-(2’-chloro)phenyl-1,2-dihydro-3Н-1,4-benzodiazepin-2-one (compound 6). This compound demonstrated clearly pronounced anti-inflammatory and antinociceptive properties in the acetic acid-induced writhing test (induction of visceral pain) in mice, test with carrageenan-induced paw edema in rats, and formalin test in mice. On multicellular preparations of circular smooth muscles from the fundal part of the rat stomach, we estimated the value of affinity of compound 6 (рKВ = 6.41). We hypothesize that the mechanism underlying inhibition of bradykinin (BK) receptors by compound 6 is mostly competitive. Therefore, compound 6 can be considered a promising basis for the development and synthesis of antagonists of BK receptors, which can be applied in clinical practice.