Aspirin ototoxicity has been studied on guinea pigs by shiver-audiometry and histological investigation of the cochlear duct. One dose of 350 mg/kg has provoked, after 7 h, a mean hearing loss of 18–24 dB at 0.25–8 kHz, followed by complete recovery in 3 days. The difference between the administration of 50 mg/kg/day and 350 mg/kg/day consists of a wide extension of the frequencies involved, and in about 10 dB a greater hearing loss. In both cases, no appreciable recovery of hearing was observed after 22 days (the histological investigations were negative). The biochemical pathogenesis of aspirin ototoxicity is discussed and periodical audiometric controls before and during salicylate treatment are recommen