The Comparative Toxicogenomics Database (CTD) is a public website and research tool that curates scientific data describing relationships between chemicals/drugs, genes/proteins, diseases, taxa, phenotypes, GO annotations, pathways, and interaction modules.The database is maintained by the Department of Biological Sciences at North Carolina State University and the Department of Bioinformatics at the MDI Biological Laboratory.CTD was launched on the web on November 12, 2004.