The biochemical characteristics and smears of the fluids in M-OME, S-OME, AOM, POMC, and AMS were studied. The fluids in S-OME and POMC had the character of transudate rather than exudate. On the other hand, M-OME, AOM, and AMS showed a more exudative or secretive nature. The character of the product from the inflammatory process of the specific condition was particularly seen in M-OME, AOM, and AMS. Thus we speculate that the chronic inflammatory process has a close relationship to the pathogenesis of OME, especially in mucoid types.