Drug checking (also "pill testing") is a broad term that refers to a range of methods for learning about the content of drug samples through an analytical process conducted in a harm reduction context. This can include field tests such as reagents and antigen strips ("test strips"), which require very little specialized knowledge, or more advanced methods that require expensive equipment, software, and technical training. Some of these methods are also used in a a law enforcement context.

Erowid runs a non-profit drug checking service, DrugsData, formerly called EcstasyData.