Localized osteoclastic bone resorption is responsible for the pathological changes within the middle and inner ear, which result in hearing loss and vertigo in chronic otitis media and otosclerosis. The local control of osteoclastic bone resorption is incompletely understood. Various small, locally active molecules, cytokines, have been shown to affect resorptive processes. Additionally, prostaglandins and their inhibitors have been shown to modulate the resorptive process in a number of in vitro studies. In this study, indomethacin, a cyclooxygenase inhibitor, was tested in a model of localized bone resorption, the pressurized gerbil bulla. After the experimental period, indomethacin was found to inhibit the number of osteoclasts and the resorptive area on the inner surface of the bulla. Therefore, it is likely that endogenous cyclooxygenase metabolites are intermediates in the sequence of cellular events, which results in localized bone resorption as in some systemic models.