PubChem is a free database of chemical compounds. PubChem is maintained by the National Center for Biotechnology Information of the United States ( National Center for Biotechnology Information, NCBI), a component of the U.S. National Library of Medicine (United States National Library of Medicine, NLM), which is part of the National Institute of Health of the USA ( National Institutes of Health, NIH) is.

PubChem consists of three interconnected databases:

  • PubChem Substance ( 38.6 million entries / January 2008): Structural formulas, synonyms, ID codes and descriptions
  • PubChem Compound ( 18.4 million entries / January 2008): validated chemical information to describe the entries of the substances in PubChem Substance database
  • PubChem BioAssay ( 832 entries / January 2008): Data from bioactivity of chemical compounds of PubChem Substance database.

PubChem is linked to the other databases of Entrez portal such as PubMed. In addition to the standard features for the text search PubChem provides a structure and substructure on the basis of drawn structural formulas. Alternatively, it can also be read from a file, a structure.

The growth of PubChem contribute more than 50 external databases.