The article presents actual data on the composition and functions of the intestinal microbiota, and examines the mechanisms of the microbiota effect on the macroorganism’s health state. The necessity and possibility of correction of microbiota are shown by the analysis of the composition and evaluation of the functions of the intestinal microbiota, and the mechanisms of the symbiotic relationship «microflora macroorganism» and the causes leading to the development of intestinal dysbiosis. The main groups of preparations (probiotics, prebiotics, synbiotics) used for correction of intestinal microbiocenosis are presented by taking into account the modern guidelines.