These investigations revealed that the treatment of patients with generalized peritonitis with ampiox, gentamicin and metronidazole, as well as with cephalosporins and metronidazole, led to the aggravation of dysbiotic disturbances in normal intestinal microflora, observed in these patients before treatment. Ciprofloxacin had a selective decontaminating effect on the intestine, which facilitated the decrease of suppuration in postoperative wounds.