Objective To explore the associated factors causing missed diagnosis for cases with secretory otitis media (SOM) and countermeasures to prevent it from occuring. Methods 106 cases with SOM, treated more than one time in hospitalization or in outpatient service without ideal therapentic effect from 1997 to 2001, were carefully and systematically analized on their all associated factors with etiology of the lesion, in order to review the tactics in diagnosis and treatments for them. Results Missed diagnosis in causal lesions related with SOM was seen a-mong 39 patients in the group of cases, lea...