MeSH Term Finder
Type a topic in everyday words — “heart attack”, “high blood pressure” — and find the MeSH heading PubMed indexes it under, with its definition, entry terms, tree numbers, and narrower and broader headings. Add headings to a basket and copy a ready-to-paste PubMed search string. Free, no sign-up.
Search for a topic to find its MeSH heading, entry terms, tree numbers and a PubMed search string.
How to Use the MeSH Term Finder
- 1. Search a topic. Use plain words or a term you already know. The tool searches MeSH headings and their entry terms together, so a search for “heart attack” leads to the heading Myocardial Infarction.
- 2. Open a heading. Choose a result to see its definition, tree numbers, entry terms and the headings above and below it. Click a related heading to move through the tree.
- 3. Add it to the PubMed string. Add every heading that fits your question to the basket. They are joined with OR into one concept block.
- 4. Choose the options and copy. Decide whether to explode, whether to require a major topic, and which title/abstract words to include. Copy the string or open it in PubMed.
What MeSH Is
Medical Subject Headings (MeSH) is the National Library of Medicine's controlled vocabulary for describing the subject of biomedical articles. Indexers assign headings to MEDLINE articles so that one heading finds every article on a topic, whatever words the authors used. That is how a search for “myocardial infarction” also finds papers that say “heart attack”.
- Heading (descriptor) — the preferred name of a concept, such as Myocardial Infarction.
- Entry terms — synonyms and variants that lead to the heading, such as Heart Attack. They make useful title/abstract words for databases that do not map terms for you.
- Tree numbers — the heading's positions in the MeSH hierarchy, such as C14.280.647.500. A heading can sit in several trees, and the first letter names the category: C is Diseases, D Chemicals and Drugs, E Techniques and Equipment, F Psychiatry and Psychology, N Health Care.
- Subheadings — qualifiers such as diagnosis or therapy that narrow a heading to one aspect. The tool lists the ones each heading allows.
Explode, Major Topic and Free Text
| Option | PubMed syntax | Effect |
|---|---|---|
| Explode (default) | "Myocardial Infarction"[Mesh] | Finds the heading and every heading below it in the tree. |
| No explode | "Myocardial Infarction"[Mesh:NoExp] | Finds the heading only, not the narrower ones. |
| Major topic | "Myocardial Infarction"[Majr] | Only articles where the heading is a main point of the article. |
| Title/abstract word | "Heart Attack"[tiab] | Finds the words themselves, whether or not the article is indexed. |
Why add free-text words to a MeSH search? New records can appear in PubMed before they are indexed, and some records — publisher-supplied content, for example — never receive MeSH headings. A search that is only MeSH misses them. A search that is only free text misses articles that use other words. The usual answer is both, joined with OR — what the tool builds when the title/abstract option is on.
A Worked Example
Searching “heart attack” finds no heading of that name but one entry term, Heart Attack, which belongs to the heading Myocardial Infarction. NLM added the heading to MeSH in 1966. Its tree numbers are C14.280.647.500, C14.907.585.500, C23.550.513.355.750 and C23.550.717.489.750, its narrower headings include ST Elevation Myocardial Infarction and Anterior Wall Myocardial Infarction, and its entry terms are Heart Attack, Myocardial Infarct and Cardiovascular Stroke. With the defaults, the string is:
PubMed string for Myocardial Infarction
("Myocardial Infarction"[Mesh] OR "Myocardial Infarction"[tiab] OR "Cardiovascular Stroke"[tiab] OR "Heart Attack"[tiab] OR "Myocardial Infarct"[tiab])Notice Cardiovascular Stroke: it is a genuine MeSH entry term, but a searcher interested in heart attacks will find it noisy. Open “Choose the title/abstract words” and untick any entry term that does not fit your question. This is the point of reading the entry terms rather than pasting them blind.
Limits to Keep in Mind
- This is PubMed and MEDLINE vocabulary. Embase uses Emtree, CINAHL and PsycINFO have their own headings, and the strings here are not valid there. The entry terms are still a good source of synonyms.
- MeSH changes every year. Headings are added, merged and retired; the tool reads NLM's current vocabulary. A heading's “previously indexed as” note shows how older articles were indexed — important for searches that reach back decades.
- Descriptors only. Supplementary concept records for individual chemicals and rare diseases are not searched.
- One concept block at a time. A review question has several concepts; build one block per concept, then combine them with AND. The Boolean Search Builder and the PICO Question Generator help structure that.
What Is Sent, and Where
When you press Search or open a heading, your browser sends the words you typed, or the heading's ID, to the National Library of Medicine's MeSH service at id.nlm.nih.gov. It needs no key. Nothing goes to CitationEasy and nothing is saved. The vocabulary itself is produced by the National Library of Medicine.
Frequently Asked Questions
- What is a MeSH term?
- A MeSH term is a heading from the National Library of Medicine's Medical Subject Headings vocabulary. Indexers use headings to describe what an article is about, so searching a heading finds articles on the topic even when their wording differs.
- How do I find the right MeSH term for my topic?
- Search the topic in everyday words. This tool looks through heading names and entry terms together, so a lay phrase leads to the official heading. You can also check the terms on a few relevant PubMed articles you already have, in the “MeSH terms” list below the abstract.
- What does “explode” mean in MeSH?
- Exploding a heading means searching it together with every narrower heading beneath it in the tree. PubMed does this automatically; add NoExp to the tag to turn it off. Exploding Myocardial Infarction also searches ST Elevation Myocardial Infarction and the other headings below it.
- What is the difference between a MeSH term and an entry term?
- The MeSH term, or heading, is the official name NLM indexes under. Entry terms are alternative names that lead to it. Searching an entry term in PubMed is mapped to the heading, and in other databases entry terms are useful free-text synonyms.
- What are MeSH tree numbers?
- Tree numbers are codes that place a heading in the MeSH hierarchy. Each extra group of digits is one level deeper, so C14.280 is a child of C14. The letter at the start names the category, such as C for Diseases.
- Why combine MeSH with title and abstract words?
- Because recent and non-MEDLINE records may not have MeSH headings yet, and because indexing is not perfect. Joining the heading and its free-text words with OR catches both the indexed and the unindexed articles.
- Can I use these strings in Embase or Scopus?
- No. The [Mesh] and [tiab] tags are PubMed syntax. Embase uses Emtree headings with its own field codes, and Scopus has its own syntax. Use the entry terms as synonyms and rewrite the string for each database.