The presented master thesis deals with the monitoring of the influence of polysaccharides which are used as an additive in the cosmetic products, on the monitored types of bacteria which are part of the skin microbiome. And it also deals with the study the effect of polysaccharides as prebiotics on selected species of bacteria that are part of the skin microbiome. Two polysaccharides were selected to determine the effects on the skin microbiome: Nanomoist and PoLevan S. The first part of the thesis focuses on the literature search which deals with skin anatomy, skin diseases and skin microbiome and its function. The experimental part is focused on monitoring changes in the quantity of selected microorganisms of the skin microbiome, before and after application of polysaccharides to the skin using qPCR. Staphylococcus epidermidis, Cutibacterium acnes, Escherichia coli and Micrococcus luteus were monitored. The PCR products were detected by agarose gel electrophoresis. The bacterium Staphylococcus epidermidis was detected on the skin to the greatest extent, especially after the application of the polysaccharides Nanomoist and PoLevan S. Thus, a positive effect of both polysaccharides on the growth of this bacterium was found.