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
• Please note: The 2021 DTD files are to be used with 2021 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)

• 2021 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)