The relationship between the distribution of eosinophils and epithelial damage of the nasal mucosa in nasal allergy was investigated by means of hematoxylin and eosin staining and a technique of immunohistochemistry using the anti-human EG2 mouse monoclonal antibody that reacts with the secreted form of eosinophil cationic protein (ECP). Nasal mucosa tissue of 26 adult nasal allergy patients and of 24 adult non-allergic rhinitis patients was removed surgically. Eosinophilia in the nasal mucosa of the allergy group was greater than that in the non-allergy group. A great number of ECP positive eosinophils accumulating in the nasal mucosa of the allergy group were mostly degranulated at the superficial layer of the lamina propria. Desquamation of the epithelium was observed mainly in the area of eosinophilia with degranulation of the secreted form of ECP in the nasal allergy group.