PubMed vs MEDLINE: What's the Difference?

MEDLINE is NLM's curated bibliographic database of journal articles indexed with MeSH; PubMed is the free search system that includes MEDLINE and also other records, such as articles awaiting indexing, publisher-supplied citations and content from PubMed Central. All MEDLINE records are in PubMed, but not all PubMed records are in MEDLINE.

What differs

• MEDLINE: records from journals selected by NLM and indexed by NLM staff or automated processes with MeSH terms.
• PubMed: a larger set that includes MEDLINE records, in-process and publisher-supplied records, and some records from PubMed Central or other sources not indexed for MEDLINE.

For the precise current definitions, consult the NLM fact sheet on how MEDLINE, PubMed and PMC differ.

Why it matters for searching

• Records not yet indexed lack MeSH terms, so a MeSH-only search misses them. Add free-text terms.
• A search limited to "MEDLINE" excludes recent unindexed records and non-MEDLINE content.
• When describing methods, state that you searched "PubMed" or "MEDLINE via PubMed" accurately, and give the date and platform.

Illustrative example

Invented for teaching. A recent article appears in PubMed but has no MeSH terms yet. A search that uses only the MeSH heading for its topic will not retrieve it, while a title/abstract search with relevant keywords will.

Practical wording for methods sections

Examples of accurate statements are: "We searched PubMed (including MEDLINE) on 1 March 2026 using the following strategy" or "We searched MEDLINE via the Ovid platform". These differ because the platform and the record set differ. Journals and reviewers increasingly expect the platform, the date and the full strategy, in line with PRISMA-S. If you apply a MEDLINE subset filter in PubMed, say so, because it excludes records that are not yet indexed.

Common pitfalls

• Writing "we searched MEDLINE" when you used the PubMed interface without a subset limit.
• Assuming every PubMed record is indexed.

Key takeaways

• MEDLINE is a curated subset of PubMed.
• Combine MeSH and free text so unindexed records are found.
• Describe your source accurately in methods.

This page is general educational information about research methods. It is not medical, legal or regulatory advice; follow your institution's ethics board and your target journal's instructions.