Why do ants like Listerine? The other day I was brushing my teeth when I noticed something interesting: a little line of ants walking around the sink and making their way to the bottle of Cool Mint Listerine that I had on the counter. And they were actually climbing the bottle and looking under the cap, where there was residue from Listerine drying away.
This wasn’t the first time I had seen that. A few days earlier I had noticed the same effect, but directly in the sink. Some drops of the Cool Mint Listerine had fallen, and were attracting ants.
Now, this wasn’t the typical ant invasion you normally see when you drop a cookie crumb or leave a piece of candy out where they can find it. There weren’t that many ants going after my Listerine, but there was a group of them there. And that got me wondering: why on earth would ants like Listerine? Listerine is not what you’d consider “food”, it’s more a chemical than anything else. And if you check the history of Listerine, you’ll find among other things it was originally sold as floor cleaner. And I sure don’t see any ants on my bottle of floor cleaner, not even on that lavender and pine smelling stuff.
So what gives? Why are ants attracted to Listerine?
So, like any other modern human being, I started my search on the internet to see what I could find on why ants like Listerine. I actually didn’t find much scientific info. Seems this is a topic that’s not really been explored much. I found a couple of forum discussions, but they were more the sarcastic college dorm discussion than anything else.
But at least I did find two things. First, I managed to confirm that it’s not my imagination: ants like Listerine, and other people see them go after the stuff too. And second, it’s not only Cool Mint Listerine that gets the ants: seems they’re also fond of Citrus flavor Listerine, and in some cases medicated mouthwash like Chlorexidine too.
I checked the label on my bottle of cool mint Listerine to see what exactly was in it, and also hopped over to Listerine’s website to check out the other varieties’ ingredients list.
Aha, here’s the stuff that makes ants like Listerine
Looking at the ingredients on the label, one of them jumped in my head immediately: sorbitol. Cool Mint Listerine contains Sorbitol. Sorbitol is made from sugar, specifically it’s made from corn syrup, which just to happens to be one of the best known sweeteners in the food industry. Corn syrup is the stuff that makes ants go crazy over most processed foods.
And sorbitol retains a lot of the properties of corn syrup, most importantly its sweet taste. Plus, sorbitol can be metabolized, albeit slowly. That’s probably what gets the ants to the Listerine bottle: they pick up on the sweetness and they also find the stuff is edible.
In citrus Listerine, you have the same sorbitol additive. And it’s also in Total Care Listerine, and pretty much any other flavor that tastes sweet.
Now, when ants actually get to the stuff, they probably find it’s not as wonderful as they thought. It contains alcohol or some alcohol substitute (like propylene glycol), as well as a variety of other chemicals that don’t make it part of a healthy diet. Some ants might pick up on the sorbitol and go for it, especially when the Listerine is dry and most of the alcohol is gone (which is what happens on the cap), but they sure won’t be diving into the bottle where those nasty chemicals are present in much higher concentrations.
What about Chlorexidine? Why do ants like that?
Chlorexidine is a medicated mouthwash that’s prescribed when you need to kill off large quantities of bacteria for extended periods of time, for example during or after sensitive oral procedures. Most mouthwash with chlorexidine doesn’t contain sorbitol or any kind of sweetening additive. So, why do ants go after that one?
I guess the reason why is the chlorexidine itself. These mouthwashes use a form of the chemical called Chlorexidine gluconate. Which as its name suggests, is derived from glucose. It’s not glucose, but the molecular structure and properties probably come close enough to make ants see it as a potential food source, and explore it. And just like with Listerine, they probably don’t take kindly to it once they get to the stuff.
Do I need to worry about ants in my Listerine?
For the most part, I’d say no. A few ants here and there might be disturbing to find, but they probably won’t kill you. Whatever bacteria they might have carried from your bathroom onto the bottle are probably going to be killed off by the mouthwash anyway.
If you still find it disturbing to have ants on your Listerine bottle, or on your bathroom, simply rinse off the bottle after use, and store it in a cabinet where ants are less likely to get to it. And also wipe off your countertops with a wet towel. Remember it’s mostly the drying Listerine gunk that gets ants’ attention, so if you clean that off you’re bound to see a lot less ants on there in the future.