We studied 28 patients with vestibular neuronitis treated at our hospital between 1997 and 1999. To determine the effects of steroid therapy on long-term canal prognosis and daily activity, we examined caloric tests and gave questionnaires to 12 steroid-treated and 16 nonsteroid-treated patients 2 years after onset. We found that canal improvement was 50% in the nonsteroid-treated group and 75% in the steroid-treated one. In cases with severe canal paresis (CP > or = 60%), canal improvement was 33% in the nonsteroid-treated group and 67% in the steroid-treated one. Steroid therapy at the acute stage of this disease significantly reduced the duration of spontaneous nystagmus and handicap in daily life due to dizziness induced by head and body movement, decreasing mood disturbance.