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The Smelliest Substances Known to Man

Last updated July 13, 2022

This post may contain affiliate links.

Author
Author avatar Danny Ashton

Danny as been writing about air purifiers for 10+ years. He is a major fan of home technology, which makes him the perfect person to test and evaluate products for HouseFresh

We use our noses far more than we realize. Pheromones can waft in and attract us to our partners, while sulfur smells warn us of danger from rotting food or unhygienic conditions. In this way, our sense of smell is very closely linked to memories. 

However, odors of military field toilets, rotting skunks, and rancid horseradish are some scents you might want to quickly forget. But which stinks stink the most? We did the research (so you didn’t have to) and found the smelliest chemicals of all time. 

1. Who Me?

What’s the best way to undermine someone? Make everyone think they lack basic potty training. This was the idea behind “Who Me?”, a concoction created by the Allied forces in WWII. 

In theory, Allied moles would spray the chemical onto high-ranking Nazi officers. The enemy soldiers will desert because who’s going to fight for a man who can’t even control his own bowel movements.

However the chemical was too volatile and the moles ended up smelling just as bad as the target, and so the project was decommissioned after only 2 weeks.

2. Ethyl Mercaptan (ethanethiol) 

This chemical is the secret behind the famously stinky Durian fruit. It also naturally occurs in petroleum and smells so much like death that some oil companies use vultures to pinpoint gas leaks.

It even has a claim to fame, being ranked as the Guinness Book of World Records’ “smelliest substance”. So if Durian fruit is part of your diet, it might be worth getting yourself an air purifier, if you want to keep your friends.

3. US Government Standard Bathroom Malodor (GSBM)

Designed to smell like a military field latrine, so basically like the excrement of a few hundred men who have been eating nothing but military rations was left to ferment in the sun. 

Officially, GSBM is used to test deodorants and air fresheners, however the Non-Lethal Weapons Department of the Department of Defense is funding stink bomb research using GSBM as a base, called Stench Soup. Its uses include crowd-control, mass evacuation, and target marking.

This is a military-grade stench.

4. Butyl seleno-mercaptan (C4H9SeH)

Butyl seleno-mercaptan is the molecule that makes a skunk’s spray so foul. When threatened, a skunk will spray a smelly oily substance that can be detected from 1.5 miles away and the scent can linger on for days

For most of the year skunks are loners, living and foraging alone, which is understandable if you smell like they do. However, during winter, many skunks will come together and form a communal den for warmth. We imagine this would smell similar to a student dorm, if all the students were skunks.

5. Cadaverine

The official scent of death, and as such, a chemical we are deeply programmed to find repulsive. As flesh decays, the amino acids react and create this deathly chemical. 

Fun fact: this compound is artificially synthesized to train cadaver dogs to find bodies.

6. Skatole

Skatole is the chemical responsible for the smell of human excrement. Here’s a strange fact: small amounts of skatole are used to flavor vanilla ice cream. This is because skatole only reeks in high concentrations, it occurs in very small amounts in flowers such as orange blossoms and jasmine.

This is the easiest smell for mankind to notice, as our nostrils have become particularly sensitive to it in order to protect us from sickness. Most of the time this smell is totally repulsive unless it is covered in sprinkles with a cherry on top.

7. Butyric acid

The smell of vomit can often cause others to feel nauseous, this is thanks to a chemical created in our guts called butyric acid. Butyric acid also occurs in small amounts in things like butter and the stinky cheeses – so that’s another horrific smell that can be found in dairy products.

Fun Fact: The Mold on blue cheese is called penicillium, the same bacteria used in the creation of, you guessed it, penicillin.

8. Thioacetone

Thioacetone is a highly unstable brown substance that can only be obtained at very low temperatures. It has an extremely potent, unpleasant odor, making it one of the worst-smelling chemicals.

Some smells are so bad they make you leave the room. Thioacetone makes you leave your city.

This actually happened in 1889, in Frieberg, Germany. 

Another German chemist, Julius Lewkowitsch explains:

When the freshly prepared reaction product of 100 g acetone-concentrated hydrochloric acid and hydrogen sulfide was distilled with water vapor with careful cooling, the smell spread quickly to distances of 0.74 kilometers to very remote parts of the city. Residents of the streets adjacent to the laboratory complained that the smelling substance had caused fainting, nausea and vomiting

9. Pyridine

Made from a concoction of bone oil (or coal tar) and various naturally occurring chemical compounds, pyridine is structurally related to benzene, with one methine group replaced by a nitrogen atom.

Pyridine is used in thousands of everyday products, from glue and paint, to vitamins and food flavoring – which is surprising as this stuff reeks like rancid fish. 

10. Putrescine

The chemical result of putrefaction (the decomposition of dead animals). Putrescine is an organic compound with the formula (CH₂)₄(NH₂)₂. Research shows that just a whiff of this death stink will elicit our flight or fight response.

If smells in your home are also eliciting a flight or fight response, you might want to get yourself an air putre-fier, I mean purifier.

11. Hydrogen selenide

One of the more toxic compounds on the list. Just smelling this colorless gas poisons, as it’s terrifyingly capable of clinging to the inside of your nostrils. Oh, and it’s also flammable. 

Even in very low concentrations, it is said to smell like rotten horseradish, and in higher concentrations transitions to a more rotten egg-y aroma. Lovely.

12. Rafflesia arnoldii (dead corpse flower)

Ok, it’s not a liquid chemical, but the world’s largest flower excretes a concoction of different chemicals that recreate the smells of rotting meat in order to attract flies that help it reproduce.

Whilst a very beautiful flower, we wouldn’t recommend it as a housewarming gift.

13. Trimethylamine oxide

This chemical is found more commonly in ocean sea life and is the reason that seafood smells so bad when it’s gone off. The scent is caused by a breakdown of bacteria combined with the fish enzymes. Imagine a rancid fish left out in the sun for a week. 

14. Ammonia

One part Nitrogen, three parts Hydrogen, and all parts repulsive. It’s strange to think that the same chemical we use to clean our kitchens is the same chemical that makes urine and sweat smell so bad. 

If you’ve sat next to someone stinky on the train, you have ammonia to thank for that.

15. Isovaleric Acid

This fatty acid, found in Valerian plants, appears to have an identity crisis. On the one hand, the acid has a cheesy, sweaty feet odor. On the other hand, one of its compounds is used in perfumes due to its fragrant scent.

Yes, it’s caught up in a perfume paradox.

Top 3 Best Air Purifiers for Bad Smells

Air purifiers do a great job of filtering airborne allergens and pollutants, making the air in your home much cleaner and better for your health, but do air purifiers help with bad smells?

The answer isn’t as simple as a yes or no. Air purifiers can help combat odors and volatile organic compounds (VOCs), but only if they utilize a filter with a large amount of activated carbon.

These are our top picks for dealing with strong smells:

Model
Best Overall
Best Budget Option
Best for Large Spaces
Style
Alen BreatheSmart 45i
Smart Health S
Levoit Core 600S
Pros
Minimalist design Surprisingly lightweight Quiet Optional Ionizing feature Lifetime warranty
A CADR of 185 cfm for a very fair price Pure HEPA filter and doesn’t have an ionizer Long-term cost savings are great for both electricity usage and filter replacements Looks good from an interior design perspective
Great for open floor plans and high-ceiling houses Can be connected to the Levoit app with its in-built Wi-Fi Easily transportable between rooms as it weighs just 13.7 lbs CADM is high for a unit for its price point
Cons
Replacement filters are expensive Cheapest filter option doesn’t have an activated carbon filter 3 different power cables for various regions is unnecessary and wasteful
No auto function No timer function
The pre-filter can’t be removed to clean The air quality sensor is on the back, so if it’s too close to the wall it won’t work effectively
CADR
245 CFM
185 CFM
410 CFM
Filter Technology
H13 True HEPA filter
HEPA H12 and activated charcoal (Optional)
H13 True HEPA filter
Recommended Room Size
up to 800 ft²
430 ft²
635 ft² - 1,588 ft²
Weight
6.8 kg / 15 lbs
4.5 / kg 10.1 lbs
6.2 kg / 13.7 lbs
Price
$428.98
$189.95
$299.99
Best Overall
Style
Alen BreatheSmart 45i
Pros
Minimalist design Surprisingly lightweight Quiet Optional Ionizing feature Lifetime warranty
Cons
Replacement filters are expensive Cheapest filter option doesn’t have an activated carbon filter 3 different power cables for various regions is unnecessary and wasteful
CADR
245 CFM
Filter Technology
H13 True HEPA filter
Recommended Room Size
up to 800 ft²
Weight
6.8 kg / 15 lbs
Price
$428.98
More Details
Best Budget Option
Style
Smart Health S
Pros
A CADR of 185 cfm for a very fair price Pure HEPA filter and doesn’t have an ionizer Long-term cost savings are great for both electricity usage and filter replacements Looks good from an interior design perspective
Cons
No auto function No timer function
CADR
185 CFM
Filter Technology
HEPA H12 and activated charcoal (Optional)
Recommended Room Size
430 ft²
Weight
4.5 / kg 10.1 lbs
Price
$189.95
More Details
Best for Large Spaces
Style
Levoit Core 600S
Pros
Great for open floor plans and high-ceiling houses Can be connected to the Levoit app with its in-built Wi-Fi Easily transportable between rooms as it weighs just 13.7 lbs CADM is high for a unit for its price point
Cons
The pre-filter can’t be removed to clean The air quality sensor is on the back, so if it’s too close to the wall it won’t work effectively
CADR
410 CFM
Filter Technology
H13 True HEPA filter
Recommended Room Size
635 ft² - 1,588 ft²
Weight
6.2 kg / 13.7 lbs
Price
$299.99
More Details

If you are interested in creating stinks then we also analyzed some of the worst smelling thing you can buy:

Model
Best for Living Areas
Style
Liquid Ass
Wet Farts - Potent Fart Spray - Extra Strong Stink - Hilarious Gag Gifts & Pranks for Adults or Kids - Prank Poop Stuff - Non Toxic - Smells Like Really 'Bad' Gas
Potent Wet Poop - Highly Concentrated Fart Spray - Extra Strong Stink - Prank Stuff & Joke Toys for Adults or Kids - Non Toxic
Pros
With a name like that it doesn't disappoint with smell power
Some say it's worse than liquid ass!
Smells like a porta potty in high heat
Cons
Small bottle for the price
Bottle can leak so be aware
Could be a bit extreme
Price
$10.99
$12.99
$9.99
Model
Style
Liquid Ass
Pros
With a name like that it doesn't disappoint with smell power
Cons
Small bottle for the price
Price
$10.99
More Details
Model
Style
Wet Farts - Potent Fart Spray - Extra Strong Stink - Hilarious Gag Gifts & Pranks for Adults or Kids - Prank Poop Stuff - Non Toxic - Smells Like Really 'Bad' Gas
Pros
Some say it's worse than liquid ass!
Cons
Bottle can leak so be aware
Price
$12.99
More Details
Best for Living Areas
Style
Potent Wet Poop - Highly Concentrated Fart Spray - Extra Strong Stink - Prank Stuff & Joke Toys for Adults or Kids - Non Toxic
Pros
Smells like a porta potty in high heat
Cons
Could be a bit extreme
Price
$9.99
More Details

Last update on 2022-08-11 / Affiliate links / Images from Amazon Product Advertising API

Final Thoughts

So there it is, the worst smells in the world and how to get them out of your house. We’ve learned that if you want to avoid the worst smells, steer clear of skunks, corpses, and the US military. There are some things an activated charcoal filter just won’t be able to fix.