On the basis of the analysis of 217 records of acute diffuse peritonitis peculiarities of the postoperative process of that complication in persons treated with 2 antibiotics (161) and 4 antibacterial drugs (56) were discussed. 4 risk levels were defined with an account of the inflammation process severity. The use of poly-antibiotic therapy was validated. The technique of its application is described in detail. The technique allowed to lower the frequency of postoperative complications and lethality 5-fold.