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HLT124: Basic Pharmacology for Health Science (Berube): MeSH (Medical Subject Headings)

Using MeSH Subject Headings

The Medical Subject Headings (MeSH®) thesaurus is a controlled vocabulary produced by the National Library of Medicine and used for indexing, cataloging, and searching for biomedical and health-related information and documents.


2015 MeSH includes the subject descriptors appearing in MEDLINE®/PubMed®, the NLM catalog database, and other NLM databases.

Many synonyms, near-synonyms, and closely related concepts are included as entry terms to help users find the most relevant MeSH descriptor for the concept they are seeking. In NLM's online databases, many terms entered by searchers are automatically mapped to MeSH descriptors to facilitate retrieval of relevant information.

Using MeSH Information in your Research: Entry Terms

Using MeSH Information in your Research: Qualifiers

Using MeSH Information in your Research: MeSH Tree Structures

Using MeSH Information in your Research: Concepts

MeSH Record Types

Class 1 Descriptors - Main Headings
These records are topical headings that are used to index citations in NLM's MEDLINE database, for cataloging of publications, and other databases, and are searchable in PubMed as [MH]. Most Descriptors indicate the subject of an indexed item, such as a journal article, that is, what the article is about. Descriptors are generally updated on an annual basis but may, on occasion, be updated more frequently.
Class 2 Descriptors - Publication Characteristics (Publication Types)
These records indicate what the indexed item is, i.e., its genre, rather than what it is about, for example, Historical Article. They may include Publication Components, such as Charts; Publication Formats, such as Editorial; and Study Characteristics, such as Clinical Trial.
Class 3 Descriptors - Check Tags
This class of descriptors is used solely for tagging citations that contain certain categories of information. They do not appear in the MeSH tree. Modernization has largely eliminated the need for the data type and many of the Check Tags have been changed to Class 1 headings that can be used either a MH or a Check Tag. Currently only two Class 3 descriptors remain: "Male" and "Female".
Class 4 Descriptors - Geographics
Descriptors which include continents, regions, countries, states, and other geographic subdivisions. They are not used to characterize subject content but rather physical location. They are listed in category Z of the MeSH Tree Structures.