MeSH® Memorandum of
You should read carefully the following Memorandum of Understanding.
Downloading MeSH data through this site indicates your acceptance of the
following terms and conditions.
1. MeSH Subject Authority File
MeSH (Medical Subject Headings) is the National Library of Medicine's
controlled vocabulary thesaurus. Several MeSH files are available via FTP
and have online documentation. MeSH is updated annually and users of this
information are encouraged to obtain the new year's data. The data are
generally available by mid-November of the preceding year.
MeSH Descriptors and Qualifiers are also published annually in a printed
version, consisting of an alphabetic list of subject headings as well as a
hierarchical display known as the MeSH Tree Structures. Ordering Information
2. Terms and conditions of use
No license is required to obtain the data via FTP. Use of this data is
subject to the following restrictions and by obtaining a copy of the data,
the user is understood to abide by these conditions:
a). If the use is not personal, (1) the U.S. National Library of Medicine
must be identified as the creator, maintainer, and provider of the data;
(2) the version of the data must be clearly stated by MeSH year, e.g., 1997
MeSH; and (3) if any modification is made in the content of the file, this
must be stated, along with a description of the modifications.
b). Neither the United States Government, nor any of its agencies,
contractors, subcontractors or employees makes any warranties, expressed or
implied, with respect to data contained in the database, and, furthermore,
assumes no legal liability for any party's use, or the results of such use,
of any part of the database.
c). You will not assert any proprietary rights to any portion of the
database, or represent the database or any part thereof to anyone as other
than a United States Government database.
d). The MeSH data carry an international copyright outside the United
States, its Territories or Possessions. These terms and conditions are in
effect as long as the user retains any of the MeSH data obtained from this
The data are available to all requesters, both within and outside the
United States. There is no charge for obtaining the file. Users are
required to complete an online registration form before receiving the