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Medical Subject Headings (MeSH)

What are Medical Subject Headings (MeSH)?

Medical Subject Headings (MeSH) is a comprehensive, controlled vocabulary produced by the National Library of Medicine. It is used to index, catalog, and search for articles and books in the life sciences.

MeSH is used by MEDLINE/PubMed, the NLM Catalog, and other NLM databases as a thesaurus that facilitates searching. It is available free of charge online. The registry also uses MeSH to classify which diseases are studied by trials registered in ClinicalTrials.

The MeSH vocabulary is regularly updated and contains the following main types of terms:

  • Headings, also known as descriptors, characterize the article’s subject matter. Definitions, links to related headings, and a list of similar terms (known as entry terms) typically accompany headings.
  • Subheadings, also called qualifiers, more completely describe a particular aspect of a subject and make it possible to group documents.
  • Publication types refer to the type of material the article represents.
  • Supplementary concept records (SCRs) describe substances such as chemical products and drugs that are not included in the MeSH terms.

Why is the Medical Subject Headings thesaurus important?

MeSH enables health professionals, medical librarians, and researchers to search for health-related literature more effectively. MeSh terms make it easier to:

  • Retrieve relevant articles when authors use different words or spellings to refer to the same subject. For example, many terms can refer to tumors or cancer of the breast, including breast neoplasm, breast tumor, mammary cancer, etc. The MeSH term “breast neoplasm” includes all related terms, so repeated searches with synonyms are unnecessary.
  • Find relevant papers, including those with insufficient or missing abstracts, because MeSH terms allow users to locate publications based on a keyword search.
  • Start a search with a broad term and narrow down the search using subheadings (e.g., the search for “breast cancer” offers alphabetically sorted subheadings ranging from “analysis” to “virology” that can be used to home in on a specific field of interest).