As secondary metabolites of plants, polyphenols constitute a basic barrier for microflora that is considered to be morbific and pathogenic (viruses, fungi, bacteria). When consumed with food, the polyphenols are able to produce many positive effects in the organisms of mammals (animals and human) and birds. Attributed to them are not only antioxidant properties, but also blood pressure lowering, antiinflammatory and antimicrobial properties. Thus, when reaching the intestines, the undigested polyphenols are responsible, to a large extent, for the modulation of intestinal microflora (including bacteria of the Lactobacillus genus). Rosa rugosa Thunb. is one of the plants that contains large amounts of polyphenolic compounds; it is one of the most popular species of wild rose occurring in Poland. The objective of the research study was to assess the prebiotic potential of crude and purified polyphenol extracts obtained from Rosa rugosa Thunb. pseudofruit pomace towards bacteria of the Lactobacillus genus (including strains with the verified probiotic properties). The predominant groups of  polyphenols present in the extracts were ellagotannins and procyanidins. Also free ellagic acid, flavonols, and catechins were present in the extracts. In addition, the purified extracts were characterised by a much higher content of polyphenols in comparison to crude extracts. Furthermore, studies were performed on the prebiotic potential of lyophilized extracts towards bacteria of the Lactobacillus genus (including the Lactobacillus brevis ŁOCK 0944 strain with the verified probiotic properties) using turbidimetric method. Only polyphenols at a concentration of 0.156 mg/ml has a prebiotic potential towards the Lactobacillus bacteria. Higher concentrations  of polyphenols contained in Rosa rugosa Thunb. pseudofruit acted as a factor limiting the increase in the biomass  of Lactobacillus spp. bacteria.