The Ecoli Metabolome Database (ECMDB) is a manually curated database of small molecule metabolites found in or produced by Escherichia coli (strain K12, MG1655). This database covers metabolites described in textbooks, scientific journals, metabolic reconstructions and other electronic databases. ECMDB currently contains 2717 small molecules with 1205 associated enzymes and 299 associated transporters. Each small molecule has 48 data fields describing the metabolite, its chemical properties and links to spectral and chemical databases. Each enzyme/transporter is linked to its associated metabolites and has 30 data fields describing both the gene and corresponding protein.