The location and severity of toxic responses in the noses of laboratory animals following inhalation of various compounds is attracting a growing number of researchers. This interest has arisen not only due to types of responses observed, but also because of the increased use of animal toxicological data for assessing human health risks from exposure to these compounds. This work addresses nasal dosimetry and toxicity of Inhaled Xenobiotics.; Originally Published As A Special Issue Of The journal "Inhalation Toxicology", the contributions are derived from a Chemical Industry Institute of Toxicology CIIT symposium held in September 1993 in Durham, North Carolina. The overview articles, covering topics like end points and responses of concern in humans, enable the reader to integrate information contained in later articles which treat the overview subjects in greater depth.; Next, mathematical and physical models that can be used to study the deposition of inhaled compounds in the upper respiratory tracts of humans and animals are considered. Approaches for experimental dosimetry studies and a number of dosimetry case studies are presented. The third series of articles examine chemically induced nasal responses in animals and humans. Integrating all the previous information, the final section discusses the use of nasal dosimetry and toxicity data for assessing human health implications and establishing appropriate exposure limits.