drug
A drug is a substance, excluding food or nutrients, that creates a physiological effect when consumed. Under the Federal Food, Drug, and Cosmetic Act, a drug is defined as “articles recognized in the official United States Pharmacopoeia, official Homoeopathic Pharmacopoeia of the United States, or official National Formulary, or any supplement to any of them; and (B) articles intended for use in the diagnosis, cure, mitigation, treatment, or prevention of disease in man or other animals; and (C) articles (other than food) intended to affect the structure or any function of the body of man or other animals; and (D) articles intended for use as a component of any article specified in clause (A), (B), or (C).” See: 21 U.S. Code § 321(g)(1).
A drug that is controlled by law because of the risk of harm or abuse is called a controlled substance. Drugs get scheduled by balancing their risk of abuse with their medical benefits, with Schedule I being the most dangerous and Schedule V being the least. See: 21 U.S. Code § 812.
[Last reviewed in April of 2026 by the Wex Definitions Team]
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