PubChem PubChem is an open chemistry database at the National Institutes of Health (NIH). Since the launch in 2004, PubChem has become a key chemical information resource for scientists, students, and the general public. 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.