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Cochrane Library

A guide to searching and using the Cochrane Library

Looking up MeSH terms in the Thesaurus

Many of the records within the Cochrane Library are indexed with MeSH (Medical Subject Headings). MeSH is the National Library of Medicine's thesaurus of controlled vocabulary terms (sometimes called subject headings), used for indexing articles for the Medline and PubMed databases. You can search the thesaurus for MeSH terms and use these in your search for more effective searching than textword searching alone. Thesaurus searching can improve the comprehensiveness of your search and is especially advised if you are undertaking a systematic review. 

If you'd like to find out more about thesaurus searching, take a look at our page: What are subject headings? 

You can search for MeSH terms within the Advanced Search, either from within the Search Manager tab by clicking on the MeSH button, or in the Medical terms (MeSH) search tab. Using either route you can then begin the MeSH search using the instructions below; both will achieve the same result.

  • Begin by entering a search term in the search box and then select Look up.

Screenshot of Search MeSH screen

  • The Thesaurus will try to find an exact match. In the example below the exact match for sore throat is Pharyngitis. The exact matched subject heading will be automatically selected. Always ensure the selected subject heading is appropriate for your search topic. 
  • Selected subject headings are exploded by default. This means they will automatically search for any narrower more specific subject headings too. For example, exploding Pharyngitis will also search for more specific types of sore throat such as Tonsillitis. 
  • If preferred, you can choose to search with a Single MeSH term instead (not exploding your MeSH term), but this will not include any narrower MeSH terms. Generally speaking it is best not to switch off the Explode button unless you are certain this is required. If you are unsure, check with a librarian. 
  • Once you have made your selection, select Add to Search Manager (or Add/Edit search line if you are working from within the Search Builder tab). 
  • The MeSH terms will be added to the Search Manager where it can be combined with other search lines.

selecting a mesh term screenshot

  • If there is no exact match then you could look at any suggested phrase or any word matches. For example a search for "Pregnant", won't find an exact match, however the MeSH term Pregnant Women is suggested as an option.
  • You can select a suggested subject heading by clicking on it.
  • Consider also using alternative search terms to check for MeSH Terms (e.g. Pregnancy).

Screenshot of MeSH screen showing no exact match