An International Nonproprietary Name (INN; also known as rINN, for recommended International Nonproprietary Name or pINN for proposed International Nonproprietary Name) is the official non-proprietary or generic name given to a pharmaceutical substance, as designated by the World Health Organization (WHO). The plethora of named proprietary preparations containing a given substance can lead to confusion about the identity of the active ingredient. INNs facilitate communication by providing a standard name for each substance. A similar role is played in chemistry by IUPAC names, though those are less suited to common usage, being typically very long and unwieldy. WHO issues INN names in English, Latin, French, Russian, and Spanish; Arabic and Chinese versions, although not included in the original scheme, are now also being issued.
| INN: | paracetamol |
| British Approved Name (BAN): | paracetamol |
| United States Adopted Name (USAN): | acetaminophen |
| Other generic names: | n-acetyl-p-aminophenol, APAP, p-acetamidophenol, acetamol, ... |
| Proprietary names: | Tylenol, Panadol, Panamax, Perdolan, Calpol, Doliprane, Tachipirina, Ben-u-ron, Atasol, and others |
| IUPAC name: | N-(4-hydroxyphenyl)-acetamide |