Hypereosinophilic syndromes (HES) are a group of disorders characterised by continuously elevated eosinophil count in blood and tissue, associated with eosinophil-mediated organ damage. During the 2023 General Annual Meeting of the Belgian Hematology Society, Prof. Florence Roufosse (Hôpital Erasme, Belgium), walked us through the clinical manifestations of this disease, diagnostic methods and currently available treatments. In this, a special focus was given to the emerging eosinophil-targeted therapies.