The development of new functional food products containing probiotics and prebiotics of plant origin has actual scientific and practical values. The presented study purpose is the creation of fermented milk products based on L.acidophilus with the introduction of an extract of the Sanguisorba officinalis or great burnet as a prebiotic. Extracts from the great burnet rhizomes and roots have an antimicrobial activity, specifically against the bacteria Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus with pronounced bactericidal effect on various microbes of the dysenteric and paratyphoid groups, a detrimental effect on Trichomonas, fungi of the genus Candida and Giardia. Physicochemical and microbiological indicators during ripening and storage of the obtained fermented milk products based on L.acidophilus with great burnet extracts are considered. Titratable acidity, water-holding capacity, the number of lactobacilli, viscosity, and organoleptic values of fermented milk products are analyzed. It is established that the product with great burnet dry extract at a concentration of 10^-3 g/cm^3 has maximum scores for organoleptic, physicochemical, and microbiological indicators. The developed bio-fermented milk product enriched by antioxidants from extracts of biologically active compounds of great burnet will meet the national and international consumers’ demands with recommendations for therapeutic and preventive nutrition and a healthy lifestyle.