Efficiency of individual combined antibiotic therapy of patients was estimated in comparison to the use of single antibiotics of their fixed combinations without any special control group. Since the essence of the study was practically in successive appliance of the 2 methods of therapy to the same group of the patients, it was possible to carry out theoretically probable estimation of the final result as a summation effect of both methods and to define the probable result of the 2 nd method. The study of the results of the treatment of the patients with purulent-inflammatory processes showed significant advantages of the individual combined antibiotic therapy.