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Cochrane Library

Guide to using the Cochrane Library database for research

Medical Subject Headings (MeSH)

Medical Subject Headings (MeSH) is a controlled vocabulary. A controlled vocabulary is a specified, pre-determined collection of terms. They are used to catalog and index the article records in Cochrane. MeSH terms are arranged into tree structures and are updated every year to include new developments. You cannot make up or add your own MeSH terms; you can only use one of the pre-existing terms

Why use MeSH?

MeSH are a retrieval tool that can help increase the accuracy and completeness of a search. MeSH cannot be made up and must be looked up in the MeSH Database. Each article in Cochrane is indexed with a handful of these terms. When searching on subject headings, all articles tagged with that heading will be retrieved. You can use MeSH terms in your search query to help retrieve more relevant results.

MeSH vs. Keywords

It is considered best practice to use a combination of keywords and MeSH terms in your search. The most recent articles in Cochrane do not have MeSH terms attached to them yet, and it can take up to six months to be tagged with MeSH. To ensure your search is all-encompassing, combine your MeSH terms with keywords using the boolean operator OR.

How to use MeSH

1. If you are in the main Cochrane search screen, click on "Medical terms (MeSH)" as seen above to be able to search MeSH terms.

 

2. Type your term into the Search box and click "Look up." Results will default to returning Subject headings by best match. You might have to scroll through to find the one that best fits what you're searching for.

 

3.  Once you have identified the MeSH term that best fits your keywords/topic, you will want to pay attention to a few features in MeSH

  • MeSH Definition - Each MeSH entry will have a quick definition and the year the term was introduced.
  • MeSH Tree - MeSH is organized in a hierarchy. Each entry will show you where this MeSH term falls in the hierarchy.
    • Note: You will want to pay attention to this because sometimes the terms indexed below the MeSH term you searched on might not be appropriate for your search. Other times you might find that the MeSH term above the term you searched on might be a better fit. 
  • Additional Searching Options - These two options help restrict how you search on a MeSH term
    • Explode all trees - this will include MeSH terms found below your searched term, in this hierarchy (tree) and other hierarchies. This will give you more results.
    • Single MeSH (unexploded) - will help you search on just that subject heading without blowing up the search the include subject headings below that might not be appropriate
    • Explode selected tree - this will include MeSH terms found below your searched term, in this hierarchy (tree) only.

 

4. To search on your MeSH term, you can click "View results" The results returned will be articles that have been tagged with the MeSH term that you selected. However, in this example we will combine it with our keyword searches to create a more advanced search.

 

Note: If you will be adding more than one MeSH term, it might be a better idea to click "Add to search manager". This will display your selected MeSH in the Search manager.

5. Your MeSH term(s) should now be seen in your search manager.

 

6.  After you have your searches of subject headings and keywords, you have to combine your searches together.

 

You have now completed a search that includes Cochrane's Medical Subject Headings! Search #3 is can either have the appropriate keywords or it can be tagged with the appropriate MeSH term.

Below is our previous example of "Does caffeine have an effect on children?" This shows how you could combine keywords and MeSH terms for a search that has multiple key concepts. The final search is #7. To view these results, click "547"