To carify the mechanism of Creola body formation in the sputum of bronchial asthmatics, guinea pigs were actively sensitized by intraperitoneal injection and provoked bronchial reactions by inhalation of aerosolized ascaris antigen. Then broncholalveolar lavage fluid (BALF) and lung tissue were examined by cytological and histological analyses. Agglomerated bronchial epithelial cells (CrB) appeared in the BALF obtained from guinea pigs in the asthma model. The frequency of CrB in the BALF of guinea pigs in the asthma model tended to increase with increase in the number of daily antigen pigs antigen inhalation and eosino-phils in the BALF. The histological findings of bronchi showed that infitration of eosinophils and submucosal edema in the bronchi, hypertrophy and protrusion of the papillary formation of bronchial epithelial layer to the bronchial lumen, and also desquamation of the layer. These findings were mainly seen at the central bronchi in guinea pigs after 8 days of antigen inhalation. These findings suggest that CrB is formed by the epithelial tissue damage caused by the chemial mediators of eosinophils and also by chronic bronchospasm. Their appearance may be an index for organic tissue damage in the pre-serious stage of asthma.