PubMed: Limitations of MeSH

MeSH may not be useful if...

• Your topic is a new or emerging concept for which a MeSH term does not yet exist.
• You suspect that very little has been published on your topic - meaning, again, there is probably no MeSH term.
• Your topic is a gene, unless it is a very heavily studied gene such as BRCA1 (most genes do not have MeSH terms).
• You want to retrieve recently published articles. The newest articles in PubMed may not yet be indexed for MEDLINE. There is a short lag time (a few days to many weeks) between when citations enter the PubMed database and when they are described with MeSH terms.
• An article you need is not indexed for MEDLINE. PubMed includes over 1.5 million articles that are not indexed with MeSH for MEDLINE.

In these circumstances, a basic keyword search would be the best way to retrieve articles.