After iv administration of 200 mg prednisolone in patients with perilymph fistula, concentrations of the drug in the cochlea were determined. A specially adapted LC method was used for analysis. Mean concentrations of prednisolone in the perilymphe reached 95 ng/ml after 15-25 min, and 338 ng/ml after 30-45 min. The values reached 8 and 41% of the corresponding serum concentrations, respectively.