In rodents, the larynx is a major site of histopathologic alteration following inhalation exposure to particulates, vapors, and aerosols. Specifically, the epithelial lining of a narrowly delineated region on the ventral floor of the larynges of rats and mice appears to be especially vulnerable to inhaled materials, and is recognized as a preferred site for histopathological evaluation in inhalation studies. This site is located at the base of the epiglottis, cranial to the ventral laryngeal diverticulum (ventral pouch (Fig. 1). The cranial half of the larynx is then embedded in paraffin (cut side down). The block of tissue is then slowly faced caudad to craniad until the ventral laryngeal diverticulum appears ventrally, and the arytenoid and &dquo;U&dquo; cartilages appear laterally (Fig. 2). Proceeding more