Why does Mucinex smell like millipedes?

July 24, 2011 7:22 PM

Why does guaifenesin (aka Mucinex) smell like millipedes?

Last year I had to take Mucinex so I could breathe after I got really sick. It was great because it worked, but horrible because it smelled (and maybe tasted?) like what I remember as the odor of millipedes. I have a pretty sensitive palate/nose, but I don't know much about how the sense of smell works when it comes to smell-alike chemicals.

I looked up the structure of guaifenesin and tried to find out more about the structures of the chemicals secreted by millipedes (Google search), but that's as far as I could get. Why might these things smell alike?

posted by zennie to science & nature (11 answers total)

I think it smells like rat poison, but I'm not sure if I know what rat poison smells like. Guaifenesin tastes horrible too and the pills are huge. Gross.
posted by coolsara at 7:49 PM on July 24, 2011

I always think smelly gym socks. Once I made the mistake of getting the alka seltzer-like effervescent version that you drink. Worst idea ever.
posted by bizzyb at 8:19 PM on July 24, 2011

Oh, I'm so glad I'm not the only one. I describe a certain flavor/smell as "squished bugs" and people make fun of me. Mucinex smells just like that. So does some Belgian beer. I would love to isolate and understand that chemical.
posted by tybstar at 8:53 PM on July 24, 2011 [1 favorite]

i honestly don't know if there IS a large body of knowledge on smell-alike chemicals in general...i mean outside of the knowledge that aromatic hydrocarbons (like benzene rings...the hexagon part of the guaifenesin molecule) tend to be smelly. remember, molecules are like wierd magnetic legos...add an atom to one end and the other end will suddenly twist up all funny and start behaving very differently (in all sorts of non-intuitive quantuum-mechanical ways)...like, for example, in the way they affect the smell receptors in your nose. add a hydrogen atom to a molecule that smells like 'new car' and it may start to smell like bananas, or nothing at all. add to this the fact that the human nose is MUCH more sensitive to smell than any piece of lab equipment (your nose can pick up the smell of ONE molecule of the odor of a rose), and you'll find that there isn't much in the way of an empirical science of odor (i'm generalizing greatly here of course)...most new scents (for household products, or perfumes, anyway) are usually created by mixing other, known, scents together, or creating new molecules in a mostly trial-and-error method. it's quite possible that mucinex (and it might not even be the active ingredient, but one of the other chemicals in it, or a combination of them) might have the same smelly chemicals as a millipede, or it might be a combination of odors from one mimicking the odor of one molecule from the other. OR, for all i know, it might actually be made from smashed millipedes. yuck. :P
posted by sexyrobot at 11:10 PM on July 24, 2011

FWIW, I suspect the active ingredient because the generics have the same odor.
posted by zennie at 4:33 AM on July 25, 2011

You are an evil, evil person. I will never be able to take these pills without thinking about that.

But think of it this way, it smells better than Valerian!
posted by canine epigram at 5:19 AM on July 25, 2011 [1 favorite]

At least part of this may be psychological priming based on the bug-like characters Mucinex uses in their advertising, too.
posted by anildash at 5:22 AM on July 25, 2011

I suspect it's the guaifenesin too, I know exactly the smell you're talking about and some cough syrup has it too. I've looked into this some because for a while I was smelling this scent in a wooded area near my office and was curious. According to wikipedia, the drug is derived from the guaiac tree, a plant that grows in the subtropics and tropics of the Americas (and may grow elsewhere as an ornamental). I don't know anything about this particular genus of plants or if the plant itself smells like guaifenesin (never figured out my own tree smell mystery) but I wouldn't be surprised if it did...
As for the millipedes, there could be some kind of habitat overlap (among certain species) that has resulted in shared chemical signals, or it could be completely unrelated. Might be interesting to research.
posted by Jemstar at 6:54 AM on July 25, 2011

YES! It's always smelled like wireworms to me, so much so that I have a hard time taking it regardless of how well it works. The name-brand stuff, for me, is quite a bit better -- it's coated, I think -- but it's really expensive. The cheap dollar-store generic, though, is almost a no-go for me.
posted by mudpuppie at 12:18 PM on July 25, 2011

And I would never have remembered that the bug characters were the Mucinex spokes-insects. There's no psychological association on this end.
posted by mudpuppie at 12:19 PM on July 25, 2011 [1 favorite]

Hm... tried to find some reference to such a smell from the guaiac tree, but only found references to it smelling like "tea rose."

This may be an unsolved mystery.
posted by zennie at 11:52 AM on July 27, 2011