MEDLINE/PubMed Data Documentation

Data Elements

MEDLINE/PubMed data conforms to the PubMed DTD. See our Data Elements documentation for more information.

Baseline Data

NLM produces a baseline set of MEDLINE/PubMed citation records in XML format for download on an annual basis. The annual baseline is released in December of each year. The best practice is to overwrite your local data with baseline data each year.

Baseline Files Previous Years' Baseline Statistics Query Previous Years' Baseline Data

Daily Update Files

Subsequent to the annual baseline release, NLM produces daily update files. These files include new, revised and deleted citations. If you are incorporating these files into a local database, load the baseline files first, then load the daily update files in numerical order. Revised or deleted citations should replace existing citations in your local database. More than one update file may become available on the same day.

Daily Update Files

Sample Data

We provide a sample data file that contains a representative sample of MEDLINE/PubMed records.

Sample Data

Additional Information and FAQ

If you still have questions regarding the downloading or contents of the data you may contact us by either visiting Contact Us or email us at nlmdatadistrib@nlm.nih.gov.

FAQ MEDLINE/PubMed Resources Guide Serials Data and MEDLINE Indexed Journals