Eosinophil granulocytes, usually called "eosinophils" or "eosinophiles", are granulocyte white blood cells that fight off certain parasites and infections in vertebrates. When they are activated, eosinophils release a cocktail of proteins from their granules, including heparin. Like mast cells and basophils, their main targets are parasites, and they are part causes of the syndromes called asthma and allergy. 