Some of the most disgusting odors for humans are hydrogen sulfide (rotting food), butyric acid (rotten milk), and skatole and indole (excrement). In other words, the odors linked to death, toxins and decay are the ones that most elicit a physical response from our body.
When we smell such smells, our brains give off a clear fight or run signal. We have evolved to avoid them because this increases the probability of survival .
The smell of Christmas cookies can bring comfort, while the smell of sewage can make the heart pound , probably thanks to a deep-seated drive to avoid disease-laden substances. For this reason, what is considered the most foul smell in the world, according to the Guinness Book of Records , can be translated as "standard of the bad smell of the American bathroom".
It was developed in 2001 by Pam Dalton, from the Monell Chemical Senses Center company , to test the efficiency of deodorants and fragrances. As Federico Kukso explains in his book Odorama: Cultural History of Scent :
After traveling the world looking for the most disgusting smells, this researcher developed a secret formula that would be made up of a combination of eight chemical substances. It’s so unpleasant that the volunteers started crying and gagging within seconds.