What Do Bed Bugs Smell Like? — An Entomologist Explains

Bed bug pheromones have a distinct odor.

In our article about common signs of bed bugs, we discussed picking up their smell as a potential clue that you have bed bugs at home.

As a disclaimer, bed bug odor is not a terribly reliable sign of an infestation because the amount produced by a single bug is extremely faint. By the time there are enough bed bugs to produce a noticeable smell, the infestation has already grown to a stage where you’ve probably already spotted live bed bugs or other concrete evidence.

So what do bed bugs actually smell like?

You might have heard or read online that bed bugs have a musty, slightly sweet odor similar to coriander, cilantro, or raspberries.

While this is technically correct, if you’re going around your bedroom sniffing for bed bugs based on this description, you won’t find them.

In this article, we’ll explain why that’s the case, and what bed bugs really smell like.

Video: What Do Bed Bugs Smell Like?

We asked our entomologist, Lou, and here’s how he explains it.

(Louis N. Sorkin is a Board Certified Entomologist at Entsult Associates Inc. Before that, he worked at the American Museum of Natural History since 1978.)

What Are You Actually Smelling?

Here’s an important distinction to make clear: the smell of an individual bed bug is very different from the smell of a bed bug infestation.

On an individual level, their odor comes from pheromones produced by the bed bug, which are special chemicals that they use to send signals to each other. When these pheromones are freshly emitted, the smell can smell slightly sweet or acidic—sometimes compared to cilantro or raspberries.

Normally, if a bed bug is just crawling around it won’t actively secrete these pheromones, making it difficult to notice. If you really want to get a whiff of it, grab a bed bug with forceps and it will produce alarm pheromones in response to being bothered.

Gripping a bed bug with forceps will release their alarm pheromones.

On an infestation level, the odor from pheromones is usually overpowered by the smell of dead bed bugs and fecal matter. Bed bug feces are essentially just digested blood, containing iron which oxidizes and gives off an unpleasant, rusty smell.

The odor from dead bed bugs and shed skin casings, which contain the glandular secretion reservoir, are also mixed in and results in a musty smell similar to dirty shoes or mold laundry.

An individual bed bug will secrete alarm pheromones which can be overpowered by the scent of a larger infestation.

Individual Bed Bugs Pheromones Smell Like:

Cilantro
Coriander
Citronella
Raspberry
Dark Cherry
Almonds

A bed bug infestation will smell rusty and dirty which will overpower the sweeter smell of a bed bugs alarm pheromones.

A Bed Bug Infestation Smells Like:

Dried Blood
Rust
Dirty Shoes
Damp Towels
Wet, Moldy Laundry

How Do Bed Bug-Sniffing Dogs Smell Bed Bugs?

Even for an expert like Lou, picking out bed bugs in a room by their smell is difficult. When not bothered, bed bugs don’t actively produce enough pheromones to be picked up by humans.

As we mentioned at the beginning of this article, by the time the smell of bed bugs is strong enough for a human to detect, the infestation has already gotten to a point where it’s obvious.

But for dogs, it’s a different story.

A canine inspector sniffs a couch, examining it for bed bugs.

Specialized bed bug detection canines are trained to locate live bed bugs by their smell.

Even if a bed bug is not secreting any pheromones, a dog can still pick up on the trace amounts on the bed bug itself. Not only that, but bed bug dogs can also be trained to differentiate between live bed bugs, dead bed bugs, shed skins, and even eggs.

Thanks to their powerful sense of smell, bed bug detection canines have an impressive 98% accuracy rate in finding live bed bugs, compared to the 40-60% accuracy rate of the average visual inspection by a human inspector.

Need Help Sniffing Out Bed Bugs?

At MMPC, our canine bed bug inspection teams are highly trained and certified by the National Entomology Scent Detection Canine Association (NESDCA).

All findings made by our canine inspectors are confirmed through visual inspections and followed up with objective and unbiased recommendations for treatment.

Whether you want to locate a suspected bed bug presence, monitor and prevent an infestation, or confirm a successful extermination, our bed bug dogs are here to help with maximum accuracy and reliability.

If you need help with bed bugs, contact us today!