DeCS: Health Sciences Descriptors Thesaurus Explained

DeCS (Descritores em Ciências da Saúde, in English Health Sciences Descriptors) is a multilingual thesaurus used to index and search health-science literature. It is coordinated by BIREME, the Latin American and Caribbean Center on Health Sciences Information, which operates under the Pan American Health Organization (PAHO) and the World Health Organization (WHO). It is built on the Medical Subject Headings (MeSH) of the U.S. National Library of Medicine and extends them with categories and languages that serve Latin American, Spanish, Portuguese and French-language literature.

What DeCS is: official name, operator and origin

• Official name: DeCS, Health Sciences Descriptors. The Portuguese and Spanish form is Descritores em Ciências da Saúde / Descriptores en Ciencias de la Salud, and searches for “descritores em ciências da saúde” refer to this same vocabulary.
• Operator: BIREME / PAHO / WHO, which coordinates the thesaurus.
• Created: BIREME created DeCS in 1986 to serve as a single language for indexing articles.
• Relationship to MeSH: DeCS was developed from MeSH. The National Library of Medicine governs the annual MeSH updates, and the yearly DeCS editions follow them.
• Languages: the portal is offered in English, Spanish, Portuguese and French, and the vocabulary itself is available in those four languages.
• Partners: the Universidad de Chile contributes the American Spanish version, the Instituto de Salud Carlos III the European Spanish version, INSERM the French translation of MeSH concepts, and the Université de Rouen Normandie the French version of the DeCS-exclusive categories.

DeCS is a controlled vocabulary, not a registry or an account system. There is nothing to register for in order to look a descriptor up; the portal is a search and browse tool. For the general idea of controlled vocabularies and thesauri, see the ANSI/NISO Z39.19 entry.

Who uses DeCS

DeCS serves two groups. Indexers and database producers use it to assign the same descriptor to every article on a topic, whatever language the article is written in. Searchers use it to find that literature without guessing every synonym and translation. In practice that means:

• researchers and librarians building search strategies for Portuguese-, Spanish- and French-language health literature;
• authors who need consistent keywords for an article, abstract or thesis in the health sciences;
• editors and indexers who tag content against a shared multilingual vocabulary;
• students learning how the same concept is named in several languages.

PAHO describes the portal as a place to explore descriptors, synonyms and translations available in four languages.

How DeCS differs from MeSH

DeCS is derived from MeSH; the difference is in what DeCS adds. Beyond MeSH, DeCS has its own categories: Science and Health; Health Surveillance; Public Health; Homeopathy; and Traditional, Complementary and Integrative Medicine. The PAHO announcement of the 2024 edition reports 394 new descriptors in that annual update, 311 of them coming from MeSH and 83 in categories exclusive to Latin American literature. As of the 2024 edition the thesaurus contained more than 729,000 terms, counting descriptors and synonyms, in four languages. Counts change with each annual edition, so use the edition currently shown on the portal.

If you already search PubMed with MeSH, the page on MeSH terms in PubMed explains explosion, major topic and subheadings; the same tree logic helps in DeCS.

How to search DeCS step by step

The portal is at decs.bvsalud.org. Choose your language (English, Español, Português or Français) and use the search form, which offers these options:

1. Any term: finds descriptors and synonyms that contain your words anywhere in the term.
2. Exact term: finds only an exact match to the word or phrase you type.
3. Descriptor UI: look up a descriptor by its unique identifier.
4. Hierarchical Code: look up a descriptor by its position code in the tree.
5. Any qualifier term: search the qualifiers (subheadings) that can be combined with descriptors.

Open a result to see the descriptor in the other languages, its synonyms and where it sits in the hierarchy. The portal also has a Tree View menu with Descriptors and Qualifiers, and menu entries for Updates, Current edition and Previous editions. The portal labels its current edition “2026 Edition”; check the portal for the latest. PAHO also lists a DeCS Finder, a “How to Search” toolbox and DeCS Panorama as part of the portal.

To suggest a term that is missing, use the “New term suggestion” link; the portal also has a “Contact us” page.

Using the tree structure

DeCS organizes its concepts in a tree. That lets you move to broader or narrower terms, or look at every term in the same branch, which is the quickest way to widen or narrow a search without inventing new keywords. Each position in the tree has a hierarchical code, which is why the search form can look descriptors up by that code.

How DeCS is used in evaluation and funding

DeCS itself is not an evaluation system and does not score researchers or journals. Its role is discovery and indexing: descriptors determine whether an article is found when someone searches by topic, which affects how visible health research in Portuguese and Spanish is to readers, reviewers and systematic-review teams. For funding applications and research reports that ask for keywords, choosing descriptors from a recognized thesaurus keeps your terminology consistent with how the literature is indexed. See also how to choose keywords for a research paper. Check each funder’s or journal’s own instructions on whether they ask for DeCS or MeSH terms.

DeCS, MEDLINE and other identifiers

DeCS describes subjects; it does not identify people or institutions. An ORCID iD or a Scopus Author ID identifies an author, whereas a DeCS descriptor identifies a concept. The two work side by side: an article is linked to its authors through their identifiers and to its subject through descriptors. Within DeCS, the identifiers that matter are the Descriptor UI and the Hierarchical Code, both searchable on the portal. For related background on literature databases and Latin American scholarly publishing, see the MEDLINE database and SciELO entries.

Common problems when searching or indexing with DeCS

• Too many or too few results with “Any term”. Switch to “Exact term” to find one specific descriptor, or use the tree to move up or down a level.
• Same concept, different language. Search in the language you know, then read the descriptor’s translations and use the form that matches the database you are searching.
• Looking for a MeSH heading that DeCS does not have, or the reverse. DeCS follows MeSH and adds its own categories, so a term in the DeCS-exclusive categories has no MeSH counterpart.
• Using an older edition. Annual editions follow MeSH updates; use “Current edition” or consult “Previous editions” on purpose when reproducing an older search.
• A term you need is missing. Use the “New term suggestion” form.

Frequently asked questions

What does DeCS stand for?

DeCS stands for Descritores em Ciências da Saúde (Portuguese), Descriptores en Ciencias de la Salud (Spanish), or Health Sciences Descriptors in English.

Who created DeCS?

BIREME created it in 1986 as a unique language for indexing articles. BIREME is the PAHO/WHO Latin American and Caribbean Center on Health Sciences Information.

Is DeCS the same as MeSH?

No. DeCS was developed from MeSH and follows its annual updates, but it adds its own categories and is maintained in four languages with the help of partner institutions.

Which languages does DeCS cover?

English, Spanish (American and European), Portuguese and French.

Do I have to register to use DeCS?

No. The portal is a search and browse tool for descriptors and qualifiers, and looking terms up does not involve an account or registration.

Can I suggest a new descriptor?

Yes. The portal has a “New term suggestion” link and a “Contact us” page.

Sources

All pages below were checked on 2026-10-28.

• DeCS portal, English interface (search options, Tree View, editions): https://decs.bvsalud.org/en/
• DeCS portal, About page (history, MeSH basis, categories, partners, term suggestion): https://decs.bvsalud.org/?p=26
• PAHO news item, “Updated DeCS portal: explore the 2024 edition with new descriptors”: https://www.paho.org/en/news/10-6-2024-updated-decs-portal-explore-2024-edition-new-descriptors