Histological processing of the cochlea for immunochemistry is often a compromise between good anatomical resolution and preservation of antigenicity. Techniques able to preserve tissue architecture invariably demand elevated temperatures and harsh chemicals or a combination of both. The likely result is reduced antigenicity, enzyme activity and nucleic acid integrity. We have modified an existing embedding medium for use in the cochlea that operates at physiological temperature and avoids denaturing agents and organic solvents. Tissue antigenicity is maximised and anatomical detail preserved, normally two mutually exclusive goals. The method is attractive because of its simplicity, speed and transparency for easy cochlear orientation. It is also likely to be adaptable for the infiltration of other heterogeneous structures prone to distortion during frozen sectioning. �� 2003 Elsevier B.V. All rights reserved.