Listen to one of our scientific editorial team members read this article.
Click here to access more audio articles or subscribe.

Time for a bit of fun.

Let’s countdown some of the worst lab smells. I’ll go through mine and present a tiny bit of smell science. Then, you can holler back with your own.

Without further ado, here are my top 10 worst lab smells in reverse order.

Countdown of the 10 Worst Lab Smells

10. Latex Gloves

I’ll start off gently with latex gloves. Not a truly offensive smell and far from being the worst lab smell. Just a little off-putting.

9. Autoclaved Cell Culture Waste

Ever stewed a turnip for far too long? No. If you did, it would smell like autoclaved cell culture waste. Yuck.

8. Powdered Virkon™

It looks deceptively nice, pink, and sherbert-like, but powered Virkon has an extraordinary smell. Especially if you are unfortunate enough to get a little up your nose. Paradoxically, I think the solution smells quite nice.

7. Fly Food

Moving up the food chain to something that might start to put you off your lunch—fly food.

What do they put in that stuff? Year-old bananas?

6. Formaldehyde

One thing that did put me off my lunch when I was an undergraduate was formaldehyde. I had to walk past the anatomy department every day to get to the sandwich shop and never felt much like eating after that.

5. Ammonia

Into the top five with one of the big hitters—ammonia.

Nauseating in low concentration, and if you are lazy enough to adjust the pH of your buffer solution with concentrated ammonia outside the hood, you’ll be knocked off your feet.

4. Paraformaldehyde

This is at number 4 for me for a very specific reason. I once spent an afternoon doing fixations with paraformaldehyde with, stupidly, my head in the hood (read our article on 10 Stupid Lab Safety Mistakes for a laugh).

I paid for it with a weekend in which everything tasted like paraformaldehyde, and since then, it has always been one of my worst smells.

The Putrid Podium

3. n-Butanol

This top 10 could be peppered with organic solvents, but I decided to just put in my worst—n-Butanol. Nasty, sickly stuff.

2. Cadaverine

The only reason that cadaverine is not number one is that it is not used in standard protocols (thank goodness), but it is possibly the most foul-smelling thing I have ever come across.

Cadaverine is a compound produced during the decomposition of animal tissue (it is decarboxylated lysine) and is partially responsible for the horrible smell of rotting flesh. It smells like decomposition in a bottle. Nice.

1. Beta-mercaptoethanol

I think we could all guess that beta-mercaptoethanol would be near the top of this list. It is top because it is such a gut-wrenching smell and because it seems to be released into the lab at least once a year (when the new Ph.D. students come in).

I participated spectacularly in that ritual in the first year of my Ph.D. by dropping and smashing a bottle of BME, triggering a full-scale evacuation of the lab. Ah, the memories.

Why Do Amines Smell Bad?

Amines have featured twice on our list—ammonia and cadaverine.

How many compounds ending “-ine” have you worked with that smelled absolutely fetid? Pyridine? Aniline? Spermine?

Amines are produced during proteolysis in decomposition and putrefaction. They are the smell of death. Our good friend evolution is the reason these chemicals smell foul to us. It’s a very effective way to warn of danger. This, as per all evolutionary benefits, increases our chances of passing on our genes.

Why Do Sulfur Compounds Smell Bad?

Number 1 on our list is a sulfur-based reducing that, like dithiothreitol, smells rank. Why is that?

The same answer as above.

Hydrogen sulfide (H2S) is another decomposition product. Evolution, passing on our genes, etc., etc.

This is why both amines and sulfurous compounds are responsible for some of the worst lab smells.

Fun fact: hydrogen sulfide is only about half as toxic as hydrogen cyanide. [1] And yet it’s seldom bandied about as a hazardous chemical. This is because its smell is so conspicuous, and we can smell it at such low concentrations that it rarely poses a hazard.

Is It Me or Is It a Bit Malodorous in Here?

Now I know you want to share your worst lab smells. Go on. Hit us with your worst!

Are you paranoid about poisoning yourself and your lab buddies, or just want an easy summary of safety data sheets? Download our free hazard diamond poster and pin it up in your lab.

Originally published July 2011. Reviewed and republished on June 2022.


Jiang J, Chan A, and Ali S et al. (2016) Hydrogen Sulfide—Mechanisms of Toxicity and Development of an Antidote. Sci Rep 6:20831

More 'Fun Stuff' articles


  1. TEMED smells like a little kid who pissed their pants and just kept wearing the same underwear and pants for 2 or 3 more days (it literally smells like that). 2-Mercaptoethanol is even worse! It smells exactly like the worst rotten egg fart imaginable. It is truly horrible. The 3rd worst thing I’ve ever smelled was back in 2005 or 2006. I was disposing 4 Liters of Tritiated horse urine that had a label on it which dated back to the late 1950’s. It was bad, because I had to pipette a sample before running the sample through the liquid scintillation counter in order to calculate the amount of H-3 that I disposed of. And when i finally poured the entire 4 Liters into the sink, the very small room I was in was a deathtrap of odor for 30 or more minutes. I couldn’t open the doors to ventilate it because it was a hallway. So I just left and later on heard complaints from 2 others in my dept who walked into the putrid aroma.

  2. I’ve got to say that the worst one that I have worked (even worse than BME and TEMED) is trimethylamine. It is what gives rotting fish its distinctive smell. Weighing out powdered TMA is not for the faint of heart!
    The runner up is rumen fluid (i.e. fluid from a cow’s stomach). It is probably not something that you would encounter outside of the field of animal science, but it is a powerful stench (thing vomit combined with rotting cheese and other foul things).

  3. The stink-bomb that some idiot made with decaying chewed up ham from their sandwich, that, or the BME that some idiot filled a water balloon with and dropped in the men’s bathroom.

  4. HI Nick,

    Yes, this subject was too good to pass up. A once previous job included testing sewer samples every day. Those are the samples that include all waste even human. Hydrogen sulfide was another one. I know it is poisonous. However, I couldn’t avoid the smell altogether.

    Doug B

Leave a Reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.