Home; 2) Browse; 3) Search; 4) About; 5) Help; 6) Downloads and 7) Contact Us. The ECMDB's browser (accessed via the Browse tab) can be used to browse through the database and to re-sort its contents. Six different browse options are available: 1) Metabolite Browse (Fig. 1); 2) Protein Browse; 3) Reaction Browse (Fig. 2); 4) Pathway Browse (Fig. 3); 5) Class Browse; and 6) Concentration Browse. By selecting a specific Browse option the ECMDB's content can be displayed in a synoptic tabular format with the ECMDB identifiers, names and other data displayed in re-sortable tables. Clicking on an ECMDB MetaboCard or ProteinCard button will bring up the full data content for the corresponding metabolite (Fig. 4) or the corresponding protein. The ECMDB also offers a number of Search options listed Under the Search link. These include: 1) Chem Query; 2) Text Query; 3) Sequence Search; 4) Data Extractor; and 4 other MS or NMR spectral search tools. Chem Query option allows users to sketch or to type (via a SMILES string) a chemical compound and to search the ECMDB for metabolites similar or identical to the query compound. The Sequence Search can be used to perform BLAST (protein) sequence searches against all the protein sequences contained in ECMDB. Single and multiple sequence (i.e. whole proteome) BLAST queries are supported through this search tool. It is also possible to perform detailed spectral searches of ECMDB's reference compound NMR and MS spectral data through the ECMDB's MS, MS/MS, GC/MS and NMR Spectra Search links. These tools are intended to support the identification and characterization of bacterial (mainly E. coli) metabolites using NMR spectroscopy, GC-MS spectrometry and LC-MS spectrometry. The ECMDB also contains a large number of statistical tables, with detailed information about not only its content but also about E. coli, in general. In particular, under the "About" tab, a section called "E. coli numbers and stats" contains hundreds of interesting factoids about E. coli and E. coli physiology. Many components of the ECMDB are fully downloadable, including most of textual data, chemical structures and sequence data. These may be retrieved by clicking on the Download button, scrolling through the different files and selecting the appropriate hyperlinks. Scope and access All data in ECMDB is non-proprietary or is derived from a non-proprietary source. It is freely accessible and available to anyone. In addition, nearly every data item is fully traceable and