AIM: To protect hearing during cochlear implantation with systemic administration of dexamethasone. METHODS: Seventeen normal-hearing guinea pigs were randomly allocated to receive an intravenous injection of either normal saline (control), low- (0.2 mg/kg) or high- (2 mg/kg) dose dexamethasone 60 min prior to cochlear implantation. Auditory brainstem response (ABR) threshold shifts (2-32 kHz) were estimated between pre- and 4-week-postoperative levels. RESULTS: ABR threshold shifts (8-32 kHz) observed in control and low-dose steroid groups were significantly reduced in the high-dose steroid group. CONCLUSIONS: A single, high-dose injection of intravenous dexamethasone protected hearing during cochlear implantation.