The Division of Chemical Research in Toxicology of the American Chemical Society is organizing a symposium on "DNA and Protein Modifications by Aldehydic Compounds from Lipid Peroxidation" for its national annual meeting on August 26-30, 2001 in Chicago. It is timely to organize such a symposium because of the recent discovery of these lesions as endogenous damage in cellular DNA and proteins and the rapid development in this exciting area. The research in this area has helped us to understand the chemical basis of aldehyde-induced lesions in "spontaneous" or "background" cancer and other chronic diseases associated with oxidative stress. We have invited five speakers, whose work represents the frontier of this research area, to address the symposium. The American Chemical Society does not provide any financial support for participants of this symposium and financial support from other sources is not anticipated. Funds are sought to defray the costs of invited speakers at the oral symposium session.