The article presents the results of study of species and quantitative composition of intestinal flora in volunteer students aged 18-21 years. The disbiotic abnormality of different degrees was diagnosed in 75% of students. The associations of microorganisms, in case of normobiosis and disbacteriosis degree I included predominantly representatives of normoflora, in case of disbiotic abnormality II and III degrees included both representatives of normoflora and opportunistic pathogenic microorganisms.