Hyaluronan (HA) is not only a key component of the extracellular matrix but also participates in influencing a wide range of physiological and pathophysiological processes. Its specific biological activity is widely used in the medical and cosmetic industries and in dietary supplements. Recent studies confirm the clinical efficacy of orally administered HA in musculoskeletal disorders and intestinal inflammation, as well as its positive effect on skin hydration. However, the exact mechanism of action of orally administered HA remains unclear. The aim of this work is therefore to contribute to the elucidation of the interaction of HA of different molecular weights with specific cells of the small intestine. As part of the thesis, an in vivo model of mouse intestinal loops, which were collected at an external workplace, and histological methods will be used to monitor the localization of biotin-labeled HA in goblet cells, Paneth cells, and immune cells. Another objective is to determine whether HA affects the activity of phospholipase A2 in in vitro differentiated 3T3-L1 adipocytes and U937 immune cells using an enzymatic assay. The findings obtained in this thesis will expand knowledge about the possible role of the small intestine in the action of p.o. HA.