The present invention relates to a composition comprising : - a plant extract of the family of the malvaceae, preferably of the genus althaea or malva, - a film-forming agent, preferably a neutral or anionic polysaccharide, and - a non-ionic emulsifier, preferably having a viscosifying properties, in particular, poloxamer, its use in order to protect the nasal mucosa against external attack, such that the acarids, the pollution or pollens and to prevent and / or treat the symptoms of allergic rhinitis.