Text search allows one to find chemical structures using one or more textual keywords, which may be chemical names (e.g., “aspirin”) or any word or phrase that describe molecules of interest (e.g., “cyclooxygenase inhibitors”). One can perform a text search from the PubChem homepage, by providing a text query in the search box. If the query is a phrase or a name with non-alphanumeric characters, double quotes should be used around the query. Various indices can be individually searched by suffixing a text query with an appropriate index enclosed by square brackets (for example, the query “N-(4-hydroxyphenyl)acetamide”[iupacname]). Numeric range searches of appropriate index fields can be performed using a “:” delimiter (for example, the query 100.5:200[molecularweight]for a molecular weight range search between 100.5 and 200.0 g/mol). One can see what search indices are available in PubChem from the drop-down menu on the “PubChem Compound Advanced Search Builder”, which can be accessed by clicking the “advanced” link (next to the “Go” button) on the PubChem homepage. Queries may be combined using the Boolean operators “AND”, “OR”, and “NOT”. These Boolean operators must be capitalized.