The International Life Sciences Institute (!LSI) is a scientific foundation that addresses critical health and safety issues of national and international con- cern. ILSI promotes international cooperation by providing the mechanism for scientists from government, industry, and universities to work together on cooperative programs to generate and disseminate scientific data. The mem- bers and trustees of the institute believe that questions regarding health and safety are best resolved when scientists can examine and discuss issues as an independent body separate from the political pressures of individual countries and the economic concerns of individual companies. Frequently, meaningful assessment of the risk of a test substance is hindered by the inherent inconsistencies in the system. The development and refine- ment of methods and systems to evaluate the safety of chemicals have evolved in a rapid and largely unplanned fashion. Attempts to improve the system have mainly been directed toward broad general concerns, with little attention being given to specific problems or issues. A failure to resolve these problems has frequently resulted in increased testing costs and complications in the assessment and extrapolation of the results to humans. Publicity surrounding toxicologic issues makes it difficult for governments to deal effectively with these problems. In response to these difficulties, ILSI has assembled highly qualified and renowned scientists from research institutes, universities, government, and industry with relevant scientific knowledge and expertise regarding the issues that complicate risk assessment procedures.