In recent decades, powerful anthropogenic impacts on modern ecosystems and the introduction of advances in pharmacology into medical practice have led to significant changes both in the human biocenosis itself and in the etiological structure of all infectious pathology. The traditional pathogenic agents responsible for the development of infectious diseases have been replaced by opportunistic microorganisms, which had previously exhibited their pathogenic properties comparatively rarely. Both the number and the characteristics of the pathological properties of the newly described microbes are rapidly increasing. At the same time, there are reports on the possible involvement of previously known, "normal" microorganisms in human pathology. The field of modern infectious pathology has begun to shift more and more toward the environmental problems of medicine, when all questions, from determining the etiology of a disease process to treating the patient, involve taking into account other components of the microbiocenosis. It is already obvious that the spectrum of such diseases is not limited to the traditionally known in this respect gut dysbacteriosis.