The persistent properties of the intestinal microflora as a mechanism of adaptation to the host's antimicrobial factors are substantiated. The results of determination of antilysozyme and anticomplementary activities and the inactivating abilities of the bactericidal component of interferon in enteric bacteria isolated in intestinal dysbacteriosis are outlined. Changes were found in the population structure of the Escherichia flora in relation to the severity of dysbacteriosis and a high prevalence of persistent signs were revealed in enteric bacteria. There was a correlation between the persistent signs of bacteria and the severity of intestinal microbiocenotic abnormalities. The factors of microbial persistence are proposed to be used as markers of a dysbiotic process.