In an attempt to determine the effect of a decongestant with or without an antihistamine on the ventilatory function of the eustachian tube (ET), two separate studies were conducted in 50 children who had had chronic or recurrent otitis media with effusion (OME) and in whom tympanostomy tubes had been inserted previously. The first was a double-blind study that compared the effect of an oral decongestant, pseudoephedrine hydrochloride, with that of a placebo in 22 children who developed an upper respiratory infection (URI) during an observation period. Certain measures of ET function were significantly elevated above baseline values during the URI, which was attributed to intrinsic mechanical obstruction of the ET. It was found that the oral decongestants tended to alter these parameters of ET function in the direction of the baseline (preURI) values. Even though the effect was statistically significant, the favorable changes in measurements of tubal function were only partial and were more prominent on the second day of the trial after the subjects had received four doses of the decongestant. However, the administration of nasal spray of 1% ephedrine appeared to have no apparent effect on ET function in these children. The second study was a double-blind crossover design. In this study of 28 children who did not have a URI, the effect of a decongestant-antihistamine combination (pseudoephedrine hydrochloride and chlorpheniramine maleate) was compared with that of a placebo. When the subjects were given the decongestant-antihistamine medication, there were favorable changes in certain ET function measures which were not observed when they received the placebo. Again, the response differences between the two groups were statistically significant. Even though these two studies indicated that an oral decongestant appeared to affect favorably the ET function of children who had a URI, and that the combination of an oral decongestant and antihistamine had a similar effect on tubal function in children without a URI, an evaluation of the efficacy of these commonly employed medications must await the results of controlled clinical trials in children with OME.