The Worst Smells in the World, Ranked by Chemistry

The smell

Naturalist Ernest Thompson Seton likened the odor to a mixture of perfume musk, essence of garlic, burning sulfur and sewer gas, “magnified a thousand times.” Skunks can aim it about 3 meters (10 feet), and a spray in the eyes can cause irritation and temporary blindness.

The nose is extremely sensitive to it: the detection threshold for the main compounds is given as 11.3 parts per billion.

The chemistry

The spray is mostly three small sulfur molecules called thiols: (E)-2-butene-1-thiol, 3-methyl-1-butanethiol and 2-quinolinemethanethiol. It also carries acetate versions of those thiols.

Tomato juice is a myth. It seems to work only because your nose gets tired and stops reporting. What does work is chemistry: a mix of hydrogen peroxide, baking soda and dish soap, developed by chemist Paul Krebaum in 1993, turns the thiols into odorless acids. The Humane Society of the United States endorses it for sprayed dogs. Follow a vet's or the Humane Society's instructions for amounts, because we are a satirical deodorant company.

The smell

The flower gives off “a powerful scent of rotting flesh” that can be detected up to 800 meters (half a mile) away. It warms its central spike to about 37 °C (99 °F) and releases the odor in pulses, building through the evening and peaking in the middle of the night, when carrion beetles and flesh flies are active.

The reason is pollination. The deep red color and the texture make the flower look like a piece of meat, and the warmth helps the smell travel. It is a plant that has fully committed to a bit.

The chemistry

The bouquet is a lineup of familiar offenders: dimethyl trisulfide (like Limburger cheese), dimethyl disulfide (garlic), trimethylamine (rotting fish), isovaleric acid (sweaty socks) and indole (like feces).

Blooms last 24 to 36 hours. From seed, the first bloom can take about ten years, and later ones typically come every three to seven years. That is a long time to wait for a smell, and we have colleagues who have waited longer for a promotion.

The smell

Described as one of the most putrid food smells in the world. Because of it, the fish is often eaten outdoors, and cans are sometimes punctured while submerged in a bucket of water to keep the brine from spraying.

In April 2006, Air France, British Airways, Finnair and KLM banned it, saying the pressurised cans were potentially explosive (BBC News, 1 April 2006). In 1984 a regional court in Cologne upheld a tenant's eviction over fish brine spread around a building. The landlord's side opened a can in the courtroom to show the judges what they meant.

The chemistry

Herring ferment in a salt brine for at least six months. Inside the can, bacteria keep working and produce carbon dioxide, propionic, butyric and acetic acids, and hydrogen sulfide. The gas makes the can bulge. In a 2014 warehouse fire in Sweden, a thousand cans exploded over six hours.

Note that butyric acid and hydrogen sulfide are entries #10 and #6 on this list. Surströmming is a greatest hits compilation, sold sealed.

The smell

Cadaverine's odor is listed as “very unpleasant; putrid.” Together with putrescine it is largely responsible for the foul smell of putrefying flesh.

The chemistry

Cadaverine takes its name from “cadaverous.” Both compounds were first described in 1885 by the Berlin physician Ludwig Brieger. Cadaverine is made from the amino acid lysine and is present in small amounts in living things. It is mostly famous for what happens when the living part stops.

Both are amines, the same chemical family as the trimethylamine that gives rotting fish its smell. Decay does not smell bad by accident. Particular molecules are doing it, and they have been identified, named and, in our case, admired.

The smell

Naturalist Alfred Russel Wallace wrote in 1856 that the aroma at first seemed like “rotten onions,” though he later became a fan. Travel writer Richard Sterling put it as “pig-excrement, turpentine and onions, garnished with a gym sock.”

It is banned on public transport in Singapore (the MRT) and Bangkok, and some hotels in Southeast Asia keep it out of rooms.

The chemistry

Organosulfur compounds, including diethyl trisulfide, diethyl disulfide and dimethyl sulfide, are a big part of it, and genes in the fruit control the release of methanethiol and ethanethiol, two more sulfur compounds. There are also esters, a family of molecules often behind fruity smells, so the same fruit manages sweet and sewage at once. It is the only entry here that is also a dessert.

The smell

Rotten eggs. The nose is ridiculously good at it: half of a test panel can detect it at 0.00047 parts per million (0.47 parts per billion) and half can name it at 0.0047 parts per million.

The chemistry

Here is the part that is not funny. At 100 to 150 parts per million, hydrogen sulfide paralyzes the olfactory nerve after a few breaths, and the smell disappears. The gas quickly deadens the sense of smell, so your nose is a terrible alarm for the very concentrations that are dangerous. Gas detectors exist for this reason. Stay out of manure pits, sewers and anywhere with a warning sign.

The smell

The sulfurous gas leak smell is not the gas. It is an additive that utilities put in so that a leak announces itself. Someone had a job making gas smell as bad as possible, and we consider this the most successful career in our industry.

The chemistry

The additives are sulfur compounds. The main ingredient in many blends is tert-butylthiol, often mixed with tetrahydrothiophene, and ethanethiol is used in LPG. The first liquid injection odorizer was developed in response to the New London School explosion in March 1937 and shipped that July.

If you smell gas for real, leave the building and call your gas utility or emergency number from outside. Do not wait for a deodorant to settle it.

The smell

A strong, ammonia-rich odor, “similar to that of many cleaning products.” The smell is much stronger than the taste, so first-timers are told to pinch their nose before the first bite.

Anthony Bourdain called it “the single worst, most disgusting and terrible tasting thing” he had ever eaten. On The F Word, Gordon Ramsay ate it and vomited into a bucket right after, while James May kept it down and offered to eat it again.

The chemistry

Fresh Greenland shark meat is toxic because of its high urea and trimethylamine oxide content. The traditional fix is to bury the gutted shark in gravelly sand under stones for six to twelve weeks, then hang it to dry for several months.

The smell

A cheese that earns its notorious smell once it passes about three months of age. It has been made since the 15th century in the Herve area of the former Duchy of Limburg, in what is now Belgium.

The chemistry

The smell comes from the bacterium Brevibacterium linens, which also lives on human skin and is partly responsible for body odor, foot odor especially. There is a letter in The Lancet from 1996 titled “On human odour, malaria mosquitoes, and Limburger.” We have not read it, for the same reason we do not read our own safety data sheets.

The smell

Unpleasant, similar to vomit or body odor. It is what you smell when butter goes rancid, and it is also found in Parmesan cheese, vomit and body odor, which is a lot of range for a single molecule.

The chemistry

The name comes from the Ancient Greek word for butter, where it was first found. Dogs can detect it at about 10 parts per billion. Humans need more than 10 parts per million, so a dog notices it at roughly a thousand times lower concentration. This is the scientific basis for the dog's expression.

Because of the smell, people have used it as an actual stink bomb, and in at least one reported case several people became unwell and were treated by an ambulance crew. That is the reason we stay in the lane of fictional products.