<h4>Background</h4>Mepolizumab (MEP) is the first anti Interleukin (IL)-5 add-on therapy approved for the treatment of severe refractory eosinophilic asthma.<h4>Case presentation</h4>We describe here the case of a 49 years-old woman with Aspirin-exacerbated respiratory disease (AERD), chronic rhinosinusitis, nasal polyposis and eosinophilic gastroenteritis successfully treated with MEP. Here, IL5 is linked to chronic rhinosinusitis.