The possible synergism between noise and aspirin for causing cochlear damage was examined histologically. Six chicks fed aspirin for five days and five chicks fed a normal diet only were paired and placed in sound chambers. They were exposed to a 1500-Hz tone at 115 dB sound pressure level for eight hours. The mean serum salicylate level just before noise exposure was 24 mg/dL (1.74 mmol/L). Ten days later they were killed, and the temporal bones were processed. Hair cell counts were made at 100-microns intervals throughout the length of the basilar papilla (cochlea). The noise produced a discrete cochlear lesion centered about 30% of the distance from the base to apex. The addition of aspirin did not significantly alter the extent or location of this lesion. One aspirin-fed chick had a unilateral middle ear effusion, and a striking shift in the center of damage toward the apex was noted in this cochlea.