To the Editor: Gentamicin is well known to be primarily vestibulotoxic, 1,2 although hearing loss may also occur. In this regard, some points should be made about the study by Smith et al. in the May 15 issue. First of all, no tests of vestibular function were carried out. Secondly, the ototoxic effects of the aminoglycosides may progress for weeks or months after cessation of therapy, i.e., hearing or vestibular function or both may continue to decline. In some cases, the first signs of vestibular or auditory dysfunction may occur after the completion of therapy. Therefore, a minimal follow-up period of.