The aim of the study is improving the efficiency of cows acute postpartum endometritis treatment by use of the drug Metrolek-O. For the treatment of cows acute postpartum endometritis was used the drug Metrolek-O in the dose of 40, 50 and 60 ml with an interval of 48 hours, intrauterus. For the study of blood counts during the cows treatment of the studied groups, blood was taken before and after clinical diagnosis of healing. Blood was taken from 5 cows from each group of IP-using system «Monojet» from tail vein. It was found that sick animals reduced content in the blood: hemoglobin – 22.80 g/l; erythrocytes – х1012 of 1.05 g/l; segment reflexology point pressure-nuclear neutrophils – was 4.02%; globulins – to 10.97% at simultaneous increase in quantity of leukocytes by 2,94х109 g/l and albumin – to 10.97%. When we use dose of the drug Metrolek-O – 50 ml morphological and biochemical blood parameters had large indicators that correspond to background. Drug Metrolek-O in the dose of 50 ml of the more effective as it provides normalization of the gradient of blood and recovery of animals by anti-inflammatory, antimicrobial, constant and regenerating properties, and increasing the dose to 60 ml ineffective because of the allergic properties of the drug, as evidenced by the increase of eozinophils 1.89%.