Thirty-six patients, aged 12-75 years, with dry, central tympanic membrane perforations and a negative Valsalva manouevre and/or a negative aspiration/deflation test, were included in a randomized, double-blind, placebo-controlled trial on the effect of a decongestant agent (xylometazoline chloride 0.1%) and placebo (saline 0.9%) applied directly to the pharyngeal opening of the Eustachian tube. Judged by the Valsalva manouevre, tubal patency was significantly improved after application of the active drug (P less than 0.003). In contrast, no effect was demonstrated by the aspiration test (P = 0.80) or the deflation test (P = 0.51). It is concluded that a topical decongestant improves Eustachian tube function but only at unphysiologically high pressures.