Medical terms

Medical terms have specific meanings. Introduce scientific terms and common names if that helps users, but always use the correct spelling and style.

Use capitals for proper nouns and genus names

Use an initial capital letter for medical terms only if the term is a proper noun or adjective, or if it is the name of a genus. Otherwise don’t use initial capitals for the names of:

  • diseases and viruses
  • diagnostic procedures
  • syndromes
  • anatomical parts.


  • hepatitis B
  • Hendra virus
  • foot-and-mouth disease
  • Golgi apparatus
  • Tourette syndrome
  • computed tomography
  • colon

Shortened forms

Use capital letters for acronyms and initialisms of medical terms. Spell out the full term in lower case, unless the word or term you’re shortening includes a proper name or a genus name.


  • acquired immune deficiency syndrome (AIDS)
  • drug-resistant Streptococcus pneumoniae (DRSP) disease
  • sudden infant death syndrome (SIDS)
  • intensive care unit (ICU)
  • magnetic resonance imaging (MRI)

Spelling for eponyms

Some terms are named after the people who discovered, studied or described the specific anatomical part or disease. Other terms are named after people who had a particular disease.

All of these terms are called ‘eponyms’. Eponyms appear as different types of adjectives in medical terms. They are usually possessive adjectives.

When referring to an eponym in writing, use the following rules:

  • If it is a disease named after people who had the disease, use the possessive case.
  • If it is a disease or anatomical part named after the person who discovered, studied or described it, don’t use the possessive case.


  • Lou Gehrig’s disease [Named after Lou Gehrig, a high-profile person who had the disease]
  • Legionnaires disease [Named after members of the American Legion – known as Legionnaires – who were the first documented people to have the disease]
  • Alzheimer disease [Named after Dr Alois Alzheimer, who first described the disease]
  • Down syndrome [Named after Dr John L H Down, who first described the syndrome]
  • Henle loop [Anatomical part named after anatomist Gustav Jakob Henle]

This rule doesn’t apply to names of organisations dedicated to studying certain diseases or supporting people who are affected by them. Always refer to organisations in the same way as they refer to themselves.


  • Alzheimers Association
  • Crohns & Colitis Australia

Italicise organism names

Write scientific names of infectious organisms – such as viruses, bacteria and parasites – in italics. Use an initial capital for the name of the genus only.


The bacterium Legionella pneumophila causes Legionnaires’ disease. [Legionella is the name of the genus and pneumophila is the species.]

Cite common names for pharmaceutical drugs, not brand names

Use the generic names of drugs where possible. Write them in lower case.

You can include the brand name in parentheses after the common name. Use initial capitals for brand names. Commercial terms might be trade marked: take care using product names.


  • benzoyl peroxide (Benzac)
  • paracetamol (Panadol)

Refer to medical conditions using clear and inclusive language

The language you use for some medical conditions can change as research and social understanding of the conditions evolve. Be mindful of outdated language that can perpetuate stigma or misunderstandings about the condition.

Refer to peak bodies that study the condition or that provide support and information to people affected by it.


The term ‘bipolar disorder’ replaces ‘manic depression’, a term that is no longer in use.

When you are writing about people with a medical condition, focus on the person. Use neutral language to describe the condition. Don’t label the person.

Write this

  • a person with cancer
  • people with asthma
  • a person with diabetes

Not this

  • a cancer patient
  • Asthma sufferers
  • a diabetic person

If you’re writing both the scientific and common names for a medical condition, place the scientific name in parentheses. Don’t use ‘or’. This could confuse readers into thinking they are 2 separate medical conditions.

Write this

People with pneumonia-like infections might have Legionnaires’ disease (legionellosis).

Not this

People with pneumonia-like infections might have Legionnaires’ disease or legionellosis.

Release notes

The digital edition consolidates and expands information from the sixth edition. It clarifies the use of eponyms in disease names and includes more examples than the sixth edition.

The digital edition has more information about style for proprietary drug names in guidance on commercial terms.

The Content Guide did not cover medical terms.

About this page


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Medical Journal of Australia (n.d.) Archive, MJA website, accessed 9 June 2020.

Medical Library Association (n.d.) What did my doctor say?, Medical Library Association website, accessed 9 June 2020.

Menon D (9 July 2019) ‘Disorder, condition, syndrome: what’s the difference?’, Health Writer Hub, accessed 9 June 2020.

Pharmaceutical Benefits Scheme (n.d.) Pharmaceutical Benefits Scheme, PBS website, accessed 9 June 2020.

TGA (Therapeutic Goods Administration) (2019) ‘Australian Register of Therapeutic Goods’, Regulation basics, TGA website, accessed 10 June 2020.

TGA (2019) ‘Ingredient basics’, Regulation basics, TGA website, accessed 10 June 2020.

TGA (2019) ‘Updating medicine ingredient names: list of affected ingredients’, Regulation basics, TGA website, accessed 10 June 2020.

US National Library of Medicine (2020) Medical subject headings 2020 (MeSH browser), US National Library of Medicine website, accessed 9 June 2020.

World Health Organization: Regional Office for the Eastern Mediterranean (n.d.) Unified medical dictionary, WHO website, accessed 9 June 2020.

This page was updated Wednesday 5 July 2023.