Background: To evaluate barrier protective properties of Rhinosectan® spray, a medical device containing xyloglucan, on nasal epithelial cells (MucilAir). Methods: MucilAir-Nasal, a three-dimensional organotypic (with diferent cell types) airway tissue model, was treated with the medical device Rhinosectan® (30 µL) or with controls (Rhinocort budesonide or saline solution). The protective barrier efects of Rhinosectan® were evaluated by: TEER (trans-epithelial electrical resistance) (preservation of tight junctions), Lucifer Yellow assay (preservation of paracellular fux) and confocal immunofuorescence microscopy (localization of tight junction proteins). Results: Exposure of MucilAir with Rhinosectan® protected cell tight junctions (increases in TEER of 13.1% vs −6.3% with saline solution after 1 h of exposure), and preserved the paracellular fux, even after exposure with pro-infammatory compounds (TNF-α and LPS from Pseudomonas aeruginosa 10). Results of confocal immunofuorescence microscopy demonstrated that, after treatment with the pro-infammatory mixture, Rhinosectan® produced a slight relocation of zona occludens-1 in the cytosol compartment (while Rhinocort induced expression of zona-occludens-1), maintaining the localization of occludin (similarly to negative control). Conclusions: Results of our study indicates that Rhinosectan® creates a protective physical barrier on nasal epithelial cells in vitro, allowing the avoidance of allergens and triggering factors, thus confrming the utility of this medical device in the management of nasal respiratory diseases, as rhinitis or rhinosinusitis. Keywords: Nasal obstruction, Rhinitis, Rhinosinusitis, Orgatypic 3D airway tissue model (MucilAir), Rhinosectan®, Xyloglucan, Barrier properties, Allergy, Preventive measures