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Guide to using Embase - an international biomedical and pharmaceutical database

What is Emtree?

Emtree is a list of subject headings unique to Embase

  • Biomedical terms are organized by broader and narrower terms for most subjects
  • Emtree subject headings will retrieve most associated synonyms for the entered term
  • Terms are included in these areas - drugs, diseases, medical devices, and associated life science concepts
  • The full text of journal articles are indexed in Embase, not just title and abstract as in PubMed

Searching Emtree for subject headings

Go the Embase home page and click on Emtree

Enter a term in the search box (here -  asthma) and add the term to your search as follows.

[1] Select Explode to include narrower terms in the hierarchy [2]

     Select As Major Focus to narrow results where the term (asthma) is a main topic of articles

[3]  Then either search [Take this query to Disease Search]
      Continue with adding more words/phrases [Add to Query Builder]


How does Emtree compare with MeSH (PubMed/Medline subject headings)

MeSH (Medical Subject Headings) are used to index articles and other published information in PubMed/Medline.  MeSH terms are used in much the same way as Emtree - to include synonyms and find associated broader and narrower terms.

                                                       Brief Comparison of MeSH® and Emtree® *

MeSH Emtree

Terminology is often inverted
(e.g.  leukemia, myeloid)

Terminology in natural language
(e.g. myeloid leukemia)
Does not include Emtree terms Includes all MeSH terms, many as synonyms
Many scope notes to define terms or
how terms areused or intended;
vocabulary more controlled than Emtree
Relies upon author supplied meanings
Fewer drug terms (9.250);
detailed drug information in
supplementary file
More drug terms (31,000+)**; new drug terms added
earlier and more often than MeSH; all necessary
drug information in Emtree
Fewer medical device terms More medical device terms, including trade name
indexing; medical device search form and device
subheadings thatshow relationships to related terms
(e.g adverse device events, device comparison,
device economics)

*From A Comparison of Emtree® and MeSH®, a July 2015 Elsevier Whitepaper

**Emtree contains all drug generic names described by FDA and EMA, all International Non-Proprietary Names (INNs) described by WHO from 2000, 23,000+ CAS registry numbers  and extended coverage of Trade Names described by many major pharmaceutical companies. From the Elsevier Embase fact sheet21/02/2019.

Embase Guides for Subject Headings and Indexing

From p. 11 of Embase Indexing Guide 2015

Automatic indexing for selected articles was introduced into Embase in 2009.
Three types of article are indexed in this way:

  • Conference abstracts
  • Articles in Press
  • In-Process records

Automatically indexed articles are indexed with Emtree terms, selected by an algorithm which is applied to the text of titles, abstracts and author keywords.

The algorithm is able to differentiate major and minor index terms; however, candidate terms and subheadings are not indexed. Non-Emtree indexing such as trade names, manufacturer names, clinical trial numbers and molecular sequence numbers is also not indexed.