The oto-respiratory (O-R) reflex consists of the cough reflex produced by direct mechanical stimulation of the deep portion of the posterior wall of the external auditory meatus. Because the efferent pathways are different for coughing and bronchoconstriction, some subjects can have an O-R reflex (coughing) without the oto-bronchial (O-B) reflex (bronchoconstriction). This study also states that on stimulation of the mechanoreceptors in the external ear, 20 out of 125 normal subjects (16%) presented with the O-R reflex; in 7 of the 20 subjects, bronchoconstriction ('responders') was also documented (O-B reflex). The O-B reflex was particularly evident in 3 of the 7 responders. These normal subjects referred a family history of atopy. Only through animal experimentation can the exact nervous pathway of the O-R reflex be defined. From the physiological point of view, it is difficult to imagine how this 'irritative' reflex could have a protective function against auditory aggression.