MEDLINE/PubMed Data Documentation
MEDLINE/PubMed data conforms to the PubMed DTD. See our Data Elements documentation for more information.
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.
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.
We provide a sample data file that contains a representative sample of MEDLINE/PubMed records.