The world's worst bitter: discovered, 'brewed' and tested in Scotland
Bitrex, the bitterest known substance, renders harmful chemicals undrinkable and has helped reduce poisoning incidents.
27 September 2017
A chemical compound accidentally discovered during work on dental anaesthetics almost 60 years ago is so bitter that it creates an overwhelming need to spit it out. The compound, known as Bitrex, discovered by Johnson Matthey scientists in Scotland, is transforming the safety of dangerous household, automotive and industrial chemicals worldwide.
The substance is the bitterest in the known universe and has been awarded a Guinness World record. Bitrex is harmless, but if ingested, will make the person who has consumed it spit it out quickly. A mere thimbleful of Bitrex can be tasted if added to an Olympic-sized swimming pool full of water.
"It's ironic in a way that it was research into oral anaesthetics in dentistry that led us to discover a substance that would make a patient sit up and spit out with a jolt," said Gina Mercier, the Bitrex Business Manager at Johnson Matthey.
Gina Mercier added: "Bitrex is now used by retailers and FMCG companies in more than 60 countries worldwide to ensure that substances that are made for cleaning and other applications don't end up being consumed. Many cleaning products these days have appealing fragrances and are highly concentrated due to customer demand, which makes it even more important for Bitrex to serve as a protection against accidental consumption."
As an additional safety measure, Bitrex is combined and stringently assessed for its compatibility with every product. It is taste tested in every product by humans at an independent facility, at the Bitrex Technology Centre in Scotland.
Two years after the original patent submission for Bitrex, this new chemical entity successfully gained approval from both the US and UK authorities for use in rendering industrial alcohol unsuitable for human consumption – known as denaturing. It was this application that gave Bitrex its generic chemical name, denatonium benzoate, and this new synthetic compound rapidly became the denaturant of choice in many countries around the world.
The first use of Bitrex as an active aversive agent was to help solve an unusual problem for the Danish pig farming community. Pigs had begun cannibalising each other's tails but by applying a cream containing Bitrex to the tails, this problem soon disappeared.
The product also has applications in pet safety. Anti-freeze, for instance, has a sweetness that is particularly appealing to pets. The introduction of Bitrex reduces the risk of pet mortality.
Following a rise in accidental poisonings of children from household cleaning products, Bitrex was identified as a possible remedy. Various studies were conducted which proved that Bitrex, even at very small concentrations, was effective in reducing the volume of material swallowed by a child.
UK customers of Bitrex include Tesco, Halford's, Prestone, Superdrug and Doff.
Johnson Matthey is actively involved in consumer product safety education programmes and sees Bitrex as the third line of defence in protecting children – after safe storage and child-resistant caps.
Johnson Matthey celebrates its 200 th anniversary this year. Founded as an assay business in the City of London, it is now global leader in science that makes the world cleaner and healthier – its catalytic converters, for example, prevent 40 tonnes of pollutants from entering the air every minute of every day. The company invests heavily in research and development, which has led to a series of breakthroughs over the years, creating new and unanticipated product lines.
For more information or to order your Bitrex taste test, visit the