THE PRESENCE of sterile fluid in the middle ear, not associated with nasopharyngeal tumor or barotrauma, is generally referred to as secretory or serous otitis media (SOM).1-4 It is a common nosologic entity found mainly in children5 and looked upon by most authors as a hydrops ex vacuo due to tubal obstruction.4,6 The occurrence of SOM in patients with patent eustachian tubes,1,4,7 however, has cast some doubt on the validity of this theory.1,2,8 An allergic factor is believed to be of great importanc by several authors,4,23,25 while others24,26 have not found evidence for this. The two main questions with respect to serous otitis media concern the mode of fluid formation and the reason for its retention in the middle ear. In previous reports9,27 I have demonstrated