Skip Navigation Bar

Introduction to MeSH

The following is an introduction to the Medical Subject Headings (MeSH) thesaurus, including its use and structure, as well as recent updates and availability of data. For simplest access to MeSH we suggest the MeSH Browser, an interactive Web application for searching and browsing MeSH data.

  1. Preface
  2. Structure of MeSH
  3. Data Elements in MeSH records
  4. Use of MeSH
  5. Changes to MeSH Terminology
    • MeSH Descriptors and MeSH Qualifiers are released annually to coincide with the calendar year. Typically the next year's data is released in late November of the prior year to allow time for MeSH users to update their systems. A preview of changes MeSH data can be found on our What's New page.
    • Supplemental Records (SCRs) are updated continually and released on a daily basis, Monday through Friday throughout the year. A yearly cycle of SCR updates is also done in order to synchronize SCRs with additions, subtractions, and changes made to Descriptor and Qualifiers.
    • Year End Processing (YEP) is done every year on PubMed citations in order to update existing citations with new terminology. The YEP process is sychronized with the release of MeSH so the searches using the latest MeSH vocabulary will retrieve the appropiate citations.
  6. Availability of MeSH Data