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What's New in MeSH

MeSH on Demand Version 2.0

MeSH on Demand (MOD) is a web interface that uses the NLM's Medical Text Indexer (MTI) to identify MeSH Terms in text provided by the user. After processing, MeSH on Demand returns a list of MeSH Terms that match your text. The newly released 2.0 version of MeSH on Demand was created in response to suggestions and comments from a variety of users. The redesign has a new appearance and several new features. Please see our MOD New Features page for more information.

The MeSH Browser has been upgraded.

Our programmers have totally redesigned and rebuilt it on a new more powerful platform.

  • Summary of new and different functionalities of the new MeSH Browser
    • The following options and controls are now listed along the top MeSH Bar on every page
      • Search (formerly: “Return to Entry Page”)
      • Tree View (formerly: “Navigate from tree top”)
      • MeSH Suggestions (formerly: "MeSH vocabulary suggestions")
      • MeSH on Demand (formerly found next to search options)
      • MeSH 2015 or other alternate MeSH year (formerly: "Go to 2015 MeSH")
      • Contact Us (formerly found at the very bottom of the page)
    • Search mode choice and differences between Full Word and Substring search
      • The Full Word search looks for complete words only, not strings that are part of a word, term, or sentence.
      • Substring search is most similar to the current MeSH Browser. It searches for a string of characters that are a complete term or are within a sentence or within another word.
    • Search Results
      • In the new MeSH Browser you have the choice of seeing the search results sorted by “Relevance” or “Name” (alphabetically by the name of the record that contains the Term found by the search). In comparison the current browser search results are listed alphabetically by the Term found by the search
      • The new MeSH Browser now offers you have the choice of seeing either 20 or 1000 records per page.
    • Record Display Improvements
      • Order of Fields in Main MeSH Descriptor has been changed. The Unique Identifier is just below tree number rather than listed last, and the qualifier field is not listed but given its own subpage (tab).
      • There are now separate tabs for Qualifiers, MeSH Tree Structures, and Concept views.
      • Qualifier tab now shows both the spelled-out and the 2-letter abbreviations.
      • The NLM Classification number is now shown when a MeSH term points to a single number in the NLM Classification.
    • Concepts View
      • The Concepts View has been simplified to one page that can be expanded or collapsed by clicking on the "Expand All/Collapse All" button, or by clicking on Concept terms (Preferred, Narrower, Broader or Related) or any of the entry Terms in each concept. In comparison the current MeSH Browser has three different record views.
      • The Concept Unique Identifiers (UIs) link to MeSH RDF data. For more information see: MeSH RDF Linked Data (beta) service from NLM
    • Viewing MeSH Trees
      • There are now two ways to browse in the Tree View.
        • Click on the plus sign (+) to expand the tree at a specific node. Note that the expanded node is now displayed within the context of the entire hierarchy and all nodes above your expansion point are available for navigation on your screen.
        • Click on the MeSH term to go to the MeSH Descriptor record for that tree node.

We redesigned our FTP Site for easier MeSH downloads

Our FTP download site:  now includes separate directories for each release year of MeSH. In addition, we created the folder "MESH_FILES" with the latest release files that are updated every morning Monday - Friday. The yearly release folders span from 2011 to the latest full release which occurs in November of the preceding year (for example, 2016 MeSH was released in November of 2015). A single directory is also included for earlier files from 1999-2010. We hope that making these archive copies more readily available to the public will be useful for those of us that are interested in studying the history MeSH terminology as it progressed over the years.

Note that distributed MeSH files are freely available to the public provided that you agree to our Memorandum of Understanding.


MeSH FTP Directory Structure:

MeSH FTP FoldersDescription
      1999-2010 Includes all annual release files from 1999-2010
Separate folders for MeSH years 2011 through 2016
      MESH_FILES The most recent MeSH files, updated Monday - Friday

Subfolders included under year folder

Folder NameDescription
asciimesh MeSH ASCII files
meshtrees Headings with Tree Nodes
mtms MeSH translation files
marc MeSH/MARC files
newterms New MeSH terms and term changes
xmlmesh MeSH files in XML format

MeSH data file naming convention using 2016 MeSH year example:

ASCII MeSH File NamesDescription
c2016.bin Supplemental Records for year 2016
d2016.bin Descriptor Records for year 2016
q2016.bin Qualifier Records for year 2016
mtrees2016.bin MeSH headings with tree nodes for 2016
meshnew2016.txt New Descriptor preferred terms for 2016
mnchg2016.txt Tree changes for 2016
mshd2016.txt All Descriptor preferred terms for 2016
replace2016.txt Deleted and replaced Descriptor headings
XML* MeSH File NamesDescription
desc2016.xml Descriptor Records for year 2016
supp2016.xml Supplemental Records for year 2016
qual2016.xml Qualifier Records for year 2016
pa2016.xml Pharmacological Actions of MeSH chemicals
*Note files ending with gz, and zip are compressed XML files
MeSH/MARC File Names*Description
20160901_label_marc_change.bin MeSH/MARC Update Label File for Sept 1, 2016


MeSH/MARC Full Label File for Sept 1, 2016
20160901_marc_change.bin MeSH/MARC Update File for Sept 1, 2016
20160901_marc_full.bin MeSH/MARC Full Release Files for Sept 1, 2016
*Note MeSH/MARC files now start with YearMonthDate. i.e. 20160101 = Jan 1, 2016