Introduction: Corticoids are often used in medicine, mainly for their anti-inflammatory properties. Although their action in the inner ear is not well known, they are employed to treat diseases like sudden hypoacusis or Ménière's disease with good results. Nowadays, the intratympanic (IT) delivery is frequently used as a treatment strategy to reduce the systemic secondary effects of corticoids. Administering IT dexamethasone (DXM) is considered a safe treatment and does not alter the hearing function. Objective: Demonstrate the safety of IT dexamethasone treatment at high doses over long periods. Materials and method: This study forms part of a clinical trial. The sample comprises a group of patients with neoplastic disease, managed by using cisplatin. The treatment protocol consists in applying a daily IT dexamethasone dose of 8 mg/24 hour for the time that chemotherapy treatment lasts. The auditory threshold was evaluated by tone audiometry. A basal examination was performed and, before each cisplatin cycle, both treated ears and control contralateral ears were explored. Results: Twenty-three patients were recruited with a mean age of 60 years. The mean IT dexamethasone treatment time, with a daily administered dose of 8 mg/mL, was 8.3 weeks, within a 2- to 18-week range and a median of 8 weeks. At the end of IT dexamethasone treatment, the difference between the mean auditory threshold between the treated and the control ears did not exceed 10 dB, which was considered to be clinically significant. Discussion: The safety of IT treatment with corticoids has been demonstrated in experimental studies with animals, in which hearing did not become worse. In the works performed with patients diagnosed with sudden hypoacusis or Ménière's disease and treated with IT dexamethasone, the incidence of hypoacusis related to treatment was very low, although the typical characteristics of these pathologies may have influenced the results (fluctuating hypoacusis or spontaneous improvement). The data obtained in our study about previously healthy ears showed no significant hearing alterations in the ears treated with IT dexamethasone, even after maintaining treatment for longer periods and at higher doses than those of previously published works. Conclusion: Using high doses of IT dexamethasone treatment for long periods does not lead to significant clinical hearing alterations in humans.