In pharmacology, a drug is a chemical substance, typically of known structure, which, when administered to a living organism, produces a biological effect.[3] A pharmaceutical drug, also called a medication or medicine, is a chemical substance used to treat, cure, prevent, or diagnose a disease or to promote well-being.[1] Traditionally drugs were obtained through extraction from medicinal plants, but more recently also by organic synthesis.[4] Pharmaceutical drugs may be used for a limited duration, or on a regular basis for chronic disorders.[1]
^"Drug Definition". Stedman's Medical Dictionary. Archived from the original on 2014-05-02. Retrieved 2014-05-01 – via Drugs.com.
^H.P., Rang; M.M, Dale; J.M., Ritter; R.J., Flower; G., Henderson (2011). "What is Pharmacology". Rang & Dale's pharmacology (7 ed.). Edinburgh: Churchill Livingstone. p. 1. ISBN978-0-7020-3471-8. a drug can be defined as a chemical substance of known structure, other than a nutrient of an essential dietary ingredient, which, when administered to a living organism, produces a biological effect