Abstract
The review is devoted to the problems of microbiota and the ways of it correction employing beneficial life bacteria- probiotics. It covers the issues related to the functioning of human microbiota and its importance for the health, individual variability of microbial content, functioning of the probiotics in the human organism and the history of probiotic studies with particular focus on the microbiological investigations in the USSR. The article discusses the safety issues related to probiotics and the problems with probiotic therapy, trying to explain the reasons for the side effects caused by probiotics. The necessity of personified selection of the probiotic strain or individual microbial therapy autoprobiotics is also discussed.