The purpose of this work is to review data on the biological effectiveness of probiotics, their mechanisms of action, and the prospects for the development of new-generation preparations. Scientific and practical justification of symbiotic drugs of a new generation – metabiotics as a continuation of the probiotic concept is given. The authors discuss the literature data and their own results, which allow them to propose new approaches to the creation of symbiotic drugs. The authors scientifically substantiate the main scientific provisions of the probiotic concept for the development of new-generation symbiotic drugs: study of aspects of the cultivation of the metabolic probiotic B. bifidum strain No. 1 in appropriate nutrient media; determination of the quantitative and qualitative composition of metabolites in the probiotic producer; scientific and practical substantiation of the qualitative and quantitative composition of the experimental probiotic suspension as a biologically active additive; the effect of probiotic suspension on the metabolism, the formation of microbiocenosis and nonspecific immunity. The substantiation for the creation of new feed probiotic preparations in the form of a composition of living microorganisms with molasses-based metabolites is given, which has a certain scientific and practical significance, and is promising for use in animal diets. Studies have found that to stabilize normal microflora in suckling pigs and weanlings, it is advisable to use various drugs in the form of biologically active additives of probiotic agents and their metabolites. The article provides a scientific and practical justification of a dietary supplement for correcting the microbiocenosis of the gastrointestinal tract and some factors of cellular immunity in growing young pigs based on the probiotic microorganism B. bifidum when cultivated on a nutrient medium from molasses.