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Getting the Most out of PubMed Medline: Truncation


Truncation is a search method in which symbols are used in place of letters or words to help you broaden your search.

In PubMed, the asterisk (*) represents any group of characters, including no character. Use it at the end of the root of your term.


Hawaii* finds:   Hawaii
Hawaii Island
  toxic* finds:   toxic
toxicology, etc.

Using Truncation

Some tips for using truncation in PubMed:

  • PubMed limits the number of possible variations to 600.  If your truncated term yields over 600 variations, you will get an error message.

  • Truncating a search term in PubMed disables automatic term mapping, meaning synonyms and MeSH terms will not be added to your search.

  • Sometimes PubMed interprets a truncated term as a phrase search.  For example the search heart attack* may be searched as "heart attack"