The worst smells in the world according to science

Credits : Flickr / Aqua Mechanical

Rotten eggs to decomposing flesh, some smells really are disgusting.  However, what are the most horrendous smells in the world?

According to a study published in the Journal of Neuroscience, a bad smell comes down to it’s underlying molecular structure.  Molecular weight and electron density also appears to be directly related to the way in which we pick up scents. Heavier and more spread out molecules have a tendency to be associated with bad smells while lighter and more compact molecules give off nicer scents.

Evolution also comes into play as traditionally we are programmed to fear things that smell unpleasant in order to survive. A part of our olfactory perception is therefore innate and calibrated.  So, in reality, what are the worst smells in the world according to science?


Recent studies have revealed that Uranus, the seventh planet in our Solar System, smells of rotten eggs. This is due to large quantities of hydrogen sulphide gas present in Uranus’ atmosphere.


This exotic fruit smells so bad that it recently led to a massive evacuation at a university in Melbourne, Australia, after students feared there was a gas leak. For some people, it smells like a mixture of turpentine and onions. For others, it smells like a strong whiff of cheese or shallots, or even garbage.

After comparing the activity of it’s genes, researchers identified that a volatile sulphuric chemical compound is reason behind the plant’s unique scent.  The set of genes is known as methionine gamma-lyase or MGLs.

worst smells
Durian gives off one of the most unpleasant smells in the world according to science. Credits : Wikimedia Commons

Rafflesia arnoldii

This parasitic plant species literally smells like decomposing flesh. Found in South-East Asia, it is known as the national flower of Indonesia. The flower is also the biggest plant in the world measuring roughly one meter in diameter. However, now on the verge of extinction, this surprising plant is a protected species.

worst smells
Rafflesia arnoldii – The biggest plant in the world known for its horrendous smell. Credits : Mazzzur/iStock

Vieux Boulogne

Vieux Boulogne is the smelliest cheese in the world. In fact, a scientist put the cheese under an electronic nose and discovered it contained similar olfactory impressions to urinary tract infections and tuberculosis which are normally detected by the device.

Ancient excrement 

Excrement smells bad but it can still stink even after 700 years.  Archaeologists found this out while they excavated a medieval latrine in the Danish village of Odense.

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An example of a medieval latrine Ostia (città antica). Credits : Wikipedia

Collared Anteater (Tamandua tetradactyla)

Don’t let this animal fool you with it’s cute muzzle.  If you go near it you’d regret it in a flash.  For that matter, this anteater uses its unpleasant smell to keep visitors and undesirable predators away.  You’ve been warned!

worst smells
Tamandua tetradactyla, known as a Collared Anteater, gives off one of the worst smells in the world Credits : Wikipedia


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