A variety of solutions were tested to find a suitable solvent of cholesteatoma debris for use in clinical practice. The specimens were taken from patients suffering from cholesteatoma during middle ear surgery and incubated in a test solution at 37°Cfor 48 hours. Hydrochloric acid (1N) and sodium hydroxide (1N) had no effect to solve the debris. Urea (1ON), acetylcysteine and trypsin had a few such effect. Proteolytic agents such as sodium dodecyl sulfat e (0.1N) and cholic acid (0.1N) had greater effect but insufficient for clinical use. In contrast, a detergent which contains interfacial active agents and a certain kind of proteolytic enzyme, such as AttackR and Hi-Top R, proved to be most effective to solve the debris.