Although the antiviral agent acyclovir is currently used for the treatment of Ramsay Hunt syndrome, its effects on facial nerve and hearing recovery remain controversial. We retrospectively analyzed the effects of acyclovir-prednisone treatment in 80 Ramsay Hunt patients. Of 28 patients for whom treatment was begun within 3 days of the onset of facial paralysis, the recovery from paralysis was complete in 21 (75%). By comparison, of 23 patients for whom treatment was begun more than 7 days after onset, recovery from facial paralysis was complete in only 7 (30%). A significant difference in facial nerve recovery was found between these groups. Early administration of acyclovir-prednisone was proved to reduce nerve degeneration by nerve excitability testing. Hearing recovery also tended to be better in patients with early treatment. There was no significant difference in facial nerve outcome between intravenous and oral acyclovir treatment.