Flavonoids display various beneficial effects in the human and animal body. Their anti-inflammatory, anti-cancer, anti-bacterial properties have been shown in several studies. The above-mentioned positive effects of these compounds are often attributed to their antioxidant properties which is in close correlation to the number and position of hydroxyl groups in the molecules. Besides hydroxyl flavonoids, their methylated analogues have also significant antioxidant effect because these can modulate different protein kinase signalling pathways in the cells. Nevertheless, the information regarding their effects on intestinal epithelium is quite limited. The oxidative stress developed by intestinal infections and inflammation diseases caused by pathogen bacteria leads to serious economic and health problems in animal breeding. Alternative food and feed additives, such as quercetin and its methylated analogues, could be also effective to prevent the above-mentioned diseases. In this study, the in vitro effect of quercetin, 3-O-methylquercetin and rhamnazin (3’,7-dimethylquercetin) has been investigated in order to evaluate whether these flavonoids could attenuate lipopolysaccharide (LPS) induced oxidative stress in IPEC-J2 non-transformed porcine intestinal epithelial cells. Moreover, effect of the flavonoids on the morphology of the enterocytes was examined.