A study was done to assess the safety of gentamicin administration by a bolus method. A total of 63 patients were randomly treated with intravenous gentamicin by bolus administration (3 to 5 min) and by slow infusion (2 h). Serum gentamicin levels were measured. Renal and audiovestibular function were monitored. Pure-tone audiometry was performed at the beginning, on day 3, and at the end of therapy. The study revealed that the bolus administration was safe and nontoxic.