The objective of the present study was to determine the amount of a medicinal agent entering the tympanic cavity during catheterization of the Eustachian tube in 26 patients presenting with exudative otitis and admitted for its treatment to N.I. Pirogov Clinical Hospital No 1, Moscow. The patients were managed by combined therapy in conjunction with catheterization of the Eustachian tube using radiocontrast matter (the iodine containing (76%) preparation trazograf having viscosity identical with that of dexamethasone). The administration of trazograf was followed by multispiral CT of the temporal bones. It was shown that trazograf penetrated into the tympanic cavity during catheterization of the Eustachian tube and accumulated inside it in 19.2% and 77% of the cases respectively. This finding suggests that the therapeutic effect in the patients presenting with exudative otitis is due not only to the direct action of the pharmaceutical product being used on the site of inflammation but also to the restoration of the draining and aerating functions of the course of Eustachian tube catheterization.