Lidocaine iontophoresis is a simple anesthetizing method of the tympanic membrane and has been widely used for the myriongotomy with or without ventilating tube insertion. To evaluate the effect of lidocaine iontophoresis on the auditory pathway, change of ABR patterns was observed in rabbits using 2% and 4% of lidocaine with or without epinephrine. The threshold shifts were observed in 4% lidocaine and 4% lidocaine with epinephrine groups, and in that group it was great and the recovery was delayed. In cases with ABR pattern changes, the wave V latency was significantly prolonged without change of the wave I latency and wave V latency-intensity function curve shifted upward in parallel. These ABR pattern changes after lidocaine iontophoresis seemed to be similar with those after intravenous administration of lidocaine.