Eustachian tube dysfunction is thought the most important endogenous factor causing the serous otitis media. In addressing tne problem of maintaining patency of E-tube, some preceding workers have studied about surface tension lowering substance and surface active agent. With lavaging the E-tube and lung of the rabbit, processing this solution with Thin Layer Chromatography, we identified phospholipid in the E-tube and compared its components with pulmonary surfactant to study the physiology of the E-tube and possibility of E-tube surfactant to act as a release agent.