The informative capacity of various statistic parameters characterizing the ecology of pathogens of purulent processes was studied. Many-years' results of the routine bacteriological tests of the materials from purulent wounds in patients from surgical, traumatological and burn departments served as the study subjects. The frequency, persistence and contamination capacity of the pathogens were investigated. Data on the changes in the frequency parameter with respect to the main pathogens of wound infections in various contingents of patients were collected. In relation to the observation period and contingent of the patients, various microorganisms were found to be permanent, supplementary and casual. The use of the ecological parameters was shown to provide integrated information on the etiological role of the pathogens in the development of purulent processes. The information characterized the microbial properties which should be considered in planning the use of antibacterial drugs and estimating the efficacy of the epidemiological control.