Denatonium

Denatonium, commonly encountered as denatonium benzoate, is a chemical compound used as a bittering agent. It is a quaternary ammonium salt of benzoic acid and is widely recognized as one of the bitterest substances known. The taste is detectable at extremely low concentrations, making it highly effective for deterring ingestion without the need for large quantities.

Denatonium benzoate was discovered in the late 1950s by MacFarlan Smith, a Scottish pharmaceutical company. It is sold under brand names such as Bitrex and has been adopted internationally as a standard bitterant in consumer products to discourage ingestion.

Common applications include antifreeze and windshield washer fluids, pesticides, cosmetics, cleaning agents, solvents, nail polish remover, and various household products. In many jurisdictions, bitterants are added to products that pose a poisoning risk to children, with denatonium added in trace amounts that are intended to be safe for handling while remaining detectable by taste.

Safety and regulatory notes: Denatonium benzoate features low acute toxicity and is not typically dangerous in ordinary exposures. Its primary purpose is to deter ingestion rather than to provide poisoning treatment. Regulations regarding its use, labeling, and permissible concentrations vary by country.