Alteration of the intestinal microflora in various physiological conditions and diseases is quite common. The problem of dysbiosis has become especially urgent in connection with the widespread use of antibiotics and other antibacterial agents. The book covers the clinic, types and phases of dysbiosis on a modern scientific level. Peculiarities of its course in diseases of the food channel, atherosclerosis, malignant neoplasms, infectious diseases, etc. are considered. Much attention is paid to the diagnosis and treatment of dysbiosis. For therapists, pediatricians, infectious disease specialists, etc.