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The Australian Health Thesaurus (AHT)

Healthdirect Australia manages and maintains a thesaurus, reflecting the current Australian health and human services environment.

The Australian Health Thesaurus (AHT) is a taxonomy (or controlled vocabulary) of medical, health and human services related concepts, organised into a hierarchical structure. Other data, such as synonyms or alternative labels, are also applied to the concepts providing a rich reference source of health and related services information.

How is the thesaurus used by Healthdirect?

The thesaurus is integral to Healthdirect’s search and discovery capability across all of its sites and platforms. It is used to improve a user’s search experience, and for content management purposes.

Healthdirect uses the thesaurus to improve the user’s search experience by:

  • offering auto-suggestions of search terms
  • utilising alternative terms or synonyms to find content
  • improving the ranking in search results of the most relevant content
  • displaying facets or filters to narrow down a user’s search results
  • providing lists of related keywords a user might also want to view.

The thesaurus is used for content management purposes by displaying contextual assets, such as:

  • relevant multimedia, for example videos
  • appropriate widgets to the user's search, such as Symptom Checker and service finder tools
  • contextual locally produced content.

Information model

The thesaurus displays a broader-narrow-related information model.

An example is given below for the concept “Cysts”.

SKOS element

AHT value

Preferred label


Broader concepts


Anatomical Pathological Conditions

Narrower concepts

Ganglion Cysts

Ovarian Cysts

Dental Cyst

Breast Cyst

Pilonidal Cyst

Related concepts

Benign Tumours

Alternative labels (such as synonyms)


Hidden labels (inappropriate terms or misspellings of that term)



Any fluid-filled closed cavity or sac that is lined by an EPITHELIUM. Cysts can be of normal, abnormal, non-neoplastic, or neoplastic tissues.

A read-only version of the thesaurus is available via the link below. Users can browse or search for concepts. The thesaurus is regularly updated, after every major revision. The last modified date is displayed in the general description on the thesaurus home page.

You can access the Australian Health Thesaurus via the link below:

If you have any questions, feedback or suggestions regarding the thesaurus please contact the Healthdirect Information Management team at

The Information contained in, or accessed through, the Australian Health Thesaurus is for your general information and use only and is not intended to be used as medical advice. Please see our Terms of use for more information.

Last reviewed: May 2016

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