The daily change of the compound VIII nerve action potential(AP) caused by clicks during kanamycin(KM) treatment was observed especially in the input-output function curve and waveform, which were recorded in a manner very similar to that used in human electrocochleography.Sixteen rabbits weighing about 3kg were used for this investigation. Rabbits were equipped with an electrode made of stainless steel wire tipped with a silver ball permanently implanted on the promontory near the round window. The reference and ground electrodes were taken on a part of the head terminal of the electric plug fixed on the skull by the stainless steel wire.Rabbits were divided into two groups. One group was given daily intraperitoneal injections of KM 150mg/kg and the other was 500mg/kg. Electrocochleographic responses were recorded daily after KM injection in awake rabbits placed into a shielded sound-proof room. The stimuli used were clicks and presented at a rate of 10/sec directed from a TDH 49 receiver. The averages were set for an analysis period of 10msec. The amplified responses were averaged 1000 times and then recorded on an X-Y plotter. The cochlear microphonics were cancelled by alternating the polarity of every click.The waveform of Ap became broad with multiple peaks as the KM injection continued.The input-output function curve of Ap Nl in normal rabbits showed a two-segmented pattern, i. e, the L-curve and the H-curve much the same as man and the other animals. The change of Ap Nl input-output function curves during KM treatment was observed as follows. In an early period of KM(150mg/kg) treatment, despite of almost no change in the L-curve, the amplitude of the H-curve especially in high intensities decreased eminently. Secondly, the latency of the L-curve increased and then reduction of amplitude and increment of latency for both curves progressed gradually. Finally, with the elevation of threshold the L-curve disappeared progressively and only the H-curve was observed. In case of KM(500mg/kg) treatment, reduction of amplitude and increment of latency for both L- and H-curves were observed almost at the same time. Then the L-curve disappeared rapidly and only the H-curve was observed. The process of the change was different in accordance with quantity of KM, but finally with the elevation of threshold the L-curve disappeared and only the H-curve was observed.Recruitment with long latency at threshold, disappearance of the L-curve and steep inputoutput function curve were present in three rabbits. It was noted that summating potential was observed in the same rabbit simultaneously with recruitment.