It is well known that many eosinophils are infiltrated in the bronchial and nasal mucosa of the allergic patients, and that the eosinophil granule proteins can injure the bronchial epithelium. But it is uncertain whether the epithelial injury can occur in the nasal mucosa of the patients with allergic rhinitis and whether it is related with the eosinophil infiltration or not. The present study was made with the aim of finding out the relation between the eosinophil infiltration and epithelial injury (if present) in the nasal mucosa of guinea pigs with experimentally induced nasal allergy. We used 19 guinea pigs as allergic group, which were sensitized with ovalbumin under a series of schedule, and 16 guinea pigs as control group. Every guinea pig in allergic group had the titer of the specific IgE not less than 1 : 8, confirmed by passive cutaneous anaphylaxis reaction. The symptom score, peripheral blood and histopathology of the nasal mucosa from the inferior conchae were examined in both groups. And then, partial correlation and multiple regression analysis were done. The results were as follows ; 1) The eosinophils, goblet cells, mast cells and epithelial loss of the nasal mucosa were found significantly more in allergy group than in control group. 2) The more infiltrated the eosinophils were, the more the epithelial loss of the nasal mucosa was. But the epithelial loss was not related with the specific IgE titer, the number of goblet or mast cells. In conclusion, it was suggested that the epithelial injury occurred in the nasal mucosa of guinea pigs with nasal allergy and it was related with the eosinophil infiltration.