material entity drug substance https://en.wikipedia.org/wiki/Drug drug Oliver He drug material See: https://github.com/CIDO-ontology/cido/issues/24 . This term needs more discussion. It was added because the current 'drug product' appears not to be aappropriate for our cases of COVID-19 drugs tested valid against viral infection experimentally in vivo or in vitro as seen in our paper: https://www.preprints.org/manuscript/202003.0413/v1. Oliver A drug is a material entity that causes a change in an organism's physiology or psychology when consumed.