The National Toxicology Program (NTP) is a unit of the U.S. Department of Health and Human Services. NTP coordinates toxicology research and testing activities within the Department and provides information about potentially toxic chemicals to regulatory and research agencies and the public. NTP is the world leader in designing, conducting, and interpreting animal assays for toxicity and carcinogenicity. Their web home page is http://ntp-server.niehs.nih.gov/.