Chronic otitis media is an inflammatory disease with bone destruction as well as loss of ossicles in mastoid bone and middle ear. Chronic otitis media with cholesteatoma-induced bone destruction is associated with severe bone destruction that more complications occurred, especially and mechanisms of bone destruction is proposed to explain the bone resorption by cholesteatomas : Osteoclastic cellular destruction, mechanical pressure necrosis, degradation by enzmes. Based on these theories, to clarify specific mechanisms underlying cholesteatoma-induced bone destruction, we used the immunofluorescence staining of the IL-1α on the squamous epithelium of cholesteatoma and normal EAC skin. The cholesteatoma tissue and normal EAC skin taken during surgery were immediately frozen to -80℃, and frozen sections 6μm thick were cut with cryotome. Monoclonal mouse anti-human IL-1α IgG was used as the primary antibody, and FITC rabbit anti mouse IgG was used as the secondary antibody. Our immunofluorescence study revealed that fluorescence positive staining is seen in all layers of epidermis on both cholesteatoma and EAC skin, particularly in basal layer and stratum spinosum. The brightness of fluorescence in cholesteatoma is stronger than EAC skin. But intracellular fluorescence is identified in only EAC skin. These data suggest that the bone destruction in chronic otitis media with cholesteatoma is attributed to IL-1α.