A retrospective computerized analysis of the records of patients with Meniere's disease was made to evaluate the effect of acetazolamide and chlorthalidone on the rate of hearing loss. Three groups were compared as follows: (1) 79 patients treated with chlorthalidone for 5 to 13.4 years; (2) 42 patients medicated with acetazolamide between 5 and 7.8 years; and (3) a control group of 71 patients who received only intermittent symptomatic treatment for vertigo, followed for 5 to 24.1 years. In the short term, after 2 to 6 weeks of treatment, a statistically significant decrease of the average hearing loss was observed with both chlorthalidone and acetazolamide. In the long term, more than 5 years, no preventive effect on the deterioration of the hearing loss could be detected. Both acetazolamide and chlorthalidone can be useful for diagnostic purposes by causing a fluctuation of hearing, as well as for the management of the vertigo attacks, but it is not useful for the long-term prevention of the hearing deterioration in Meniere's disease.