Changing levels of sex hormones have been previously associated with clinical symptoms due to alterations of the respiratory mucosa. Aural manifestations, however, have not yet been studied in this regard. Eustachian tube swallow test and blood levels of estrogen were evaluated daily in 25 women undergoing induction of ovulation. Most women showed a near stable eustachian tube performance over a wide range of estrogen levels, particularly in the physiologic range. However, there is a moderate decrease in eustachian tube function with increasing estrogen levels in some women, manifested mainly at levels beyond that of the normal menstrual cycle.