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The story of how Bitrex® came to be

We thought you might ask. Find out everything you want to know about us below.

About Us

Like many important scientific discoveries, our scientists at Macfarlan Smith discovered Bitrex by accident! They quickly realised they had found a remarkable substance, which would later be recognised by the Guinness World Records as the “the most bitter stuff on earth” and has gone on to save countless lives throughout the world.

The Discovery

Denatonium benzoate was discovered by accident in 1958 while our scientists were working on a new local anaesthetic at our site in Edinburgh, Scotland. A patent was quickly registered and from there the brand Bitrex was born.

Who are Macfarlan Smith?

Macfarlan Smith is one of the world’s oldest pharmaceutical companies, founded in 1815, and is the founder and owner of the Bitrex brand.

Initial Uses

Bitrex was originally used as a deterrent in pig farming to prevent pigs from biting each other’s tails! We soon realised the essential role Bitrex could have in helping prevent accidental ingestion of products by children.

Child Safety

We partner with global brands to help make their products safer by including Bitrex. From household cleaners, pesticides and laundry detergent, to pens, paint, batteries and many more, we work with many brands to help protect children.

We regularly collaborate with our partners to help spread awareness of product safety and the role of Bitrex, educating parents and carers around the world about the importance of child safety measures.

Bitrex® Today

More products contain Bitrex and display our logo than ever before. Consumer demand for safer products is at an all-time high and is continuing to grow. We play a key role in helping brands communicate their dedication to safety.


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