About PubChem

For latest announcements, please visit the PubChem News page.


PubChem is an open chemistry database at the National Institutes of Health (NIH). “Open” means that you can put your scientific data in PubChem and that others may use it. Since the launch in 2004, PubChem has become a key chemical information resource for scientists, students, and the general public. Each month our website and programmatic services provide data to several million users worldwide.


PubChem mostly contains small molecules, but also larger molecules such as nucleotides, carbohydrates, lipids, peptides, and chemically-modified macromolecules. We collect information on chemical structures, identifiers, chemical and physical properties, biological activities, patents, health, safety, toxicity data, and many others.


Where does the data in PubChem come from? PubChem records are contributed by hundreds of data sources. Examples include: government agencies, chemical vendors, journal publishers, and more.


The amount of data in PubChem is ever-growing, please visit the PubChem Statistics page to find out what the latest data counts are.



New Web Interface

Multiple updates to the PubChem web interface were released in March 2019. The updates include a new look and feel for most PubChem content pages such as compound summaries, substance and bioassay records, patent views, and more. Furthermore, PubChem homepage and search have been completely revamped, with many more features and improvements to search functionality to come in the near future.



How To Access Previous Interface?

This new release emphasizes ease-of-access in information retrieval, but any change can be disruptive. With a strategic bookmark or two, existing workflows can be maintained. If this applies to you, read on for more details.


What About Entrez?

In the past, the majority of our users found it very difficult to navigate between multiple Entrez text search interfaces (one had to use a separate Entrez interface for compounds, substances, and bioassays), a separate structure search interface, the content pages, and the homepage. Additionally, Entrez does not support content that was added to PubChem later, such as patents.


In order to provide a better user experience, we created a unified chemical search interface that supports text search across all PubChem data collections as well as structure and molecular formula search. This unified search interface has now become the new PubChem homepage.


If you happen to be a long time PubChem Entrez user, you may have noticed that we have omitted links to Entrez on the new PubChem homepage. Do not fear, however, PubChem Entrez interfaces did not go away, and you may continue using them. For easy access we recommend bookmarking the following:


We do recognize that PubChem Entrez interfaces have some powerful features that may not be currently available in the new PubChem search interface. In the coming months, we will be examining which Entrez features users miss in the new interface, and will consider incorporating them. Please let us know what you think!


What About Structure Search?

The new PubChem search interface provides a better user experience and includes most of the features of the legacy structure search interface. However, the legacy structure search interface is still available at the following URL:



Before retiring this legacy interface, we will be examining if and how it is still being used, and which features might be missed by PubChem users. Please let us know what you think!



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