The Hazardous Substances Data Bank (HSDB) is a toxicology database on the U.S. National Library of Medicine's (NLM) Toxicology Data Network (TOXNET). It focuses on the toxicology of potentially hazardous chemicals, and includes information on human exposure, industrial hygiene, emergency handling procedures, environmental fate, regulatory requirements, and related areas. All data are referenced and derived from a core set of books, government documents, technical reports, and selected primary journal literature. Prior to 2020, all entries were peer-reviewed by a Scientific Review Panel (SRP), members of which represented a spectrum of professions and interests. Last Chairs of the SRP are Dr. Marcel J. Cassavant, MD, Toxicology Group, and Dr. Roland Everett Langford, PhD, Environmental Fate Group. The SRP was terminated due to budget cuts and realignment of the NLM.

The HSDB is organized into individual chemical records, and contains over 5000 such records. It is accessible free of charge via TOXNET. Users can search by chemical or other name, chemical name fragment, CAS registry number and/or subject terms. Recent additions include radioactive materials and certain mixtures, like crude oil and oil dispersants as well as animal toxins. As of November 2014, there are approximately 5,600 chemical specific HSDB records available.