Document Type Definitions (DTDs) for NLM Databases

The purpose of a DTD (Document Type Definition) is to define the building blocks of an XML document. It defines the document structure with a list of allowable elements. Below are the DTDs that define NLM XML data.

MEDLINE^®/PubMed^® DTD:

• pubmed_190101.dtd (01/01/19) For use with 2019, 2020 and 2021 PubMed data.

MeSH® DTDs:

• 2021 MeSH Descriptor DTD - used for MeSH Vocabulary, companion database to MEDLINE/PubMed
• 2021 MeSH Qualifier DTD
• 2021 MeSH SCR DTD
• 2021 MeSH Pharmacological Action DTD
• 2022 MeSH Descriptor DTD
• 2022 MeSH Qualifier DTD
• 2022 MeSH SCR DTD
• 2022 MeSH Pharmacological Action DTD
• Please note: The 2021 DTD files are to be used with 2021 production MeSH and 2022 DTDs are to be used with 2022 production MeSH.

For more information, see the Download MeSH Data page.

NLM Catalog DTD:

Current (2021)	Forthcoming (2022)
NLMCatalogRecordSet DTD (01/01/21)	Released December 2021

List of Serials Indexed for Online Users (LSIOU)

• 2022 NLM Serials DTD

HMD DTDs:

• 2013 IndexCatalogue DTD
• 2013 eTKeVK2 DTD

HSRProj:

• HSRProj DTD

Toxicology Databases:

• NLM CCRIS DTD (02/26/04)
• NLM ChemIDplus Subset DTD (04/28/05)
• NLM GENE-TOX DTD (02/11/02)
• NLM HSDB® DTD (04/12/04)
• NLM LactMed DTD (03/27/15)