DrugBank is a comprehensive bioinformatics and cheminformatics resource that combines detailed drug data with comprehensive drug target information. It contains over 4100 drug entries, including over 800 FDA-approved small molecule and biotech drugs, and over 3200 experimental drugs. Each DrugCard entry contains over 80 data fields, half devoted to drug/chemical data and the other half to drug target or protein data. The database is fully searchable, supporting text, sequence, chemical structure, and relational queries. It links to other databases such as KEGG, PubChem, ChEBI, PDB, Swiss-Prot, and GenBank, and includes structure viewing applets. DrugBank is available at http://redpoll.pharmacy.ualberta.ca/drugbank/. DrugBank was developed to address the 'informatics gap' between cheminformatics and bioinformatics by integrating sequence, structure, and mechanistic data about drugs and their targets. It combines data-rich molecular biology content with medicinal chemistry data. The database was compiled over four years using over a dozen textbooks, several hundred journal articles, nearly 30 electronic databases, and 20 in-house or web-based programs. It includes over 14,000 protein sequences linked to drug entries. DrugBank is divided into four major categories: FDA-approved small molecule drugs, FDA-approved biotech drugs, nutraceuticals, and experimental drugs. It is also divided into two larger categories: all FDA drugs and all compounds. DrugBank provides a wide range of tools for viewing, sorting, and extracting drug or drug target data. It supports text queries, general browsing, and specialized 'PharmBrowse' features. It also offers a local BLAST search, a chemical structure search tool, and a relational data extraction tool. These tools allow users to search for drug leads, compare drug similarities, and determine if a compound acts on a desired protein target. The database is fully searchable and contains over 16 gigabytes of data, most of which can be freely downloaded. DrugBank is a unique resource that provides comprehensive, accurate, and up-to-date information on drugs and drug targets. It is primarily focused on providing detailed molecular data needed for drug discovery and development. It includes physical property data, structure and image files, pharmacological and physiological data, and extensive molecular biological information about drug targets. DrugBank is unique in the type of data it provides and the level of integration and depth of coverage it achieves. It is the only public database we are aware of that provides significant information about the 110+ approved biotech drugs. DrugBank supports an extensive array of visualizing, querying, and search options, including a structure similarity search tool and an easy-to-use relational data extraction system. It is hoped that DrugBank will serve as a useful resource to pharmaceutical researchers, educators, students, clinicians, and the general public.DrugBank is a comprehensive bioinformatics and cheminformatics resource that combines detailed drug data with comprehensive drug target information. It contains over 4100 drug entries, including over 800 FDA-approved small molecule and biotech drugs, and over 3200 experimental drugs. Each DrugCard entry contains over 80 data fields, half devoted to drug/chemical data and the other half to drug target or protein data. The database is fully searchable, supporting text, sequence, chemical structure, and relational queries. It links to other databases such as KEGG, PubChem, ChEBI, PDB, Swiss-Prot, and GenBank, and includes structure viewing applets. DrugBank is available at http://redpoll.pharmacy.ualberta.ca/drugbank/. DrugBank was developed to address the 'informatics gap' between cheminformatics and bioinformatics by integrating sequence, structure, and mechanistic data about drugs and their targets. It combines data-rich molecular biology content with medicinal chemistry data. The database was compiled over four years using over a dozen textbooks, several hundred journal articles, nearly 30 electronic databases, and 20 in-house or web-based programs. It includes over 14,000 protein sequences linked to drug entries. DrugBank is divided into four major categories: FDA-approved small molecule drugs, FDA-approved biotech drugs, nutraceuticals, and experimental drugs. It is also divided into two larger categories: all FDA drugs and all compounds. DrugBank provides a wide range of tools for viewing, sorting, and extracting drug or drug target data. It supports text queries, general browsing, and specialized 'PharmBrowse' features. It also offers a local BLAST search, a chemical structure search tool, and a relational data extraction tool. These tools allow users to search for drug leads, compare drug similarities, and determine if a compound acts on a desired protein target. The database is fully searchable and contains over 16 gigabytes of data, most of which can be freely downloaded. DrugBank is a unique resource that provides comprehensive, accurate, and up-to-date information on drugs and drug targets. It is primarily focused on providing detailed molecular data needed for drug discovery and development. It includes physical property data, structure and image files, pharmacological and physiological data, and extensive molecular biological information about drug targets. DrugBank is unique in the type of data it provides and the level of integration and depth of coverage it achieves. It is the only public database we are aware of that provides significant information about the 110+ approved biotech drugs. DrugBank supports an extensive array of visualizing, querying, and search options, including a structure similarity search tool and an easy-to-use relational data extraction system. It is hoped that DrugBank will serve as a useful resource to pharmaceutical researchers, educators, students, clinicians, and the general public.