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ChemIDplus Subset

ChemIDplus is the National Library of Medicine's (NLM) authority file used for the identification of chemical substances cited in other NLM databases.

NLM leases a ChemIDplus subset which does not include the structure or the toxicity data available from NLM's web versions of the database. Beginning October 28, 2007, it also does not include data with the source tag of USPDDN available in the web versions. Contact Terri Markward ( of the U.S. Pharmacopeial Convention, Inc., the provider of USPDDN data for ChemIDplus, for information about leasing the USPDDN data directly from USP.

See the ChemIDplus Fact Sheet for a full description of ChemIDplus.