Bed Bug Feces (Poop): What Do Their Droppings Look Like?

If you know how to identify bed bug feces, you’re able to not only spot a potential infestation but stop one.

After reading this guide, you’ll know exactly how to identify bed bug poop, meaning you can take swift action. Whether it’s being able to call in a professional before it’s too late or spotting evidence on your travels so you avoid welcoming bed bugs into your home.

What Do Bed Bug Feces Look Like?

Bed bug feces will often appear in clusters of tiny spots, streaks, or smudges. They’ll look a bit like freckles, but a gross slimy version.

It can sometimes be mistaken for mold or mildew, so you can use the following to help you identify bed bug poop:

Poop Shape

If you are looking at a collection of quite regular shapes, it could be bed bug feces. Each dropping has a uniform shape and can be found deposited in latrine clusters or more randomly along popular runs.

Poop Size

Imagine you have dotted an “i” with a marker. That’s about the size of a dropping. Although there is a slight variation in size between nymphs and adults, you are not likely to notice. 

Poop Color

Is there something on your bed that looks like a rusty dark spot? Bed bugs thrive on fresh blood and nothing else. So quite naturally, their droppings reflect their singular diet. Bed bug feces will be a dark red-brown, like blood left to stain. Sometimes it’s so dark red it looks black.

Poop Smell

Due to bed bugs solely feeding on blood, their droppings can have a rusty, musky smell to it.

However, once inspecting your mattress, it’s common of a bed bug infestation to smell more like mold or damp.

Identifying Bed Bug Poop With Wet Towel

If you’re still unsure, you can use the following test:

Take a wet paper towel and dab at a spot. Bed bug fecal matter will smudge red onto the towel when wet.

Where Will You Find Bed Bug Droppings?

Your Sheets?

It’s actually unlikely you’d ever find bed bug poop on your bedsheets because they take a long time to digest.

After bed bugs feed on their blood host, they’ll retreat back into their harborage where they’ll sleep, digest, and poop.

Your Mattress?

This is where you’ll most likely find bed bug poop. You’ll see small clusters of what may appear like freckles, mold, or mildew.

Due to bed bug feces being more liquid than solid, these stains will often be dried into the fabric or smeared in streaks across it.

According to this study on bed bugs, it’s common to find bed bugs feces close to their harborage (nest).

Can Bed Bug Droppings Cause Health Problems

It’s natural to worry about something as gross as bed bug waste causing health problems. There is no clear scientific evidence for or against any long-term health implications. However, their unwelcome presence could be a problem for some in the short term.

Some bed bug studies noticed that bed bug fecal matter contains histamine. This chemical compound is found in their aggregation pheromone, a scent secreted when bed bugs congregate.

Because of this histamine, exposure to droppings can trigger allergic reactions in allergy-prone people. The extent varies from person to person depending on the individual’s immune system response. In most cases, even in people with no known allergies, the immune reaction presents as itching at the site of the bite. Sometimes, this reaction can be so severe it needs medical intervention.

In other potentially life-threatening cases, bed bug droppings have been suspected as triggers for asthma attacks.

Investigations found that households with a bed bug infestation had higher background levels of histamine compared to households with no infestation and that bed bug fecal waste, rather than the bug itself, had a large role to play in it.

Cleaning Bed Bug Feces

As mentioned above, there is no clear evidence bed bug feces cause you any harm, so as long as you don’t have an infestation, you don’t have to clean it.

However, that’s gross, so here’s what you can do:

Often, to clean any type of poop off of a mattress people use hydrogen peroxide treatment:

  1. 8oz Hydrogen peroxide 3%
  2. 1-2 drops of dishwashing detergent
  3. Two table spoons of baking soda
  4. 1 industrial strength spray bottle (if spray bottle tube has filter, remove as this can be clogged by the baking soda)

Mix your solution into your spray bottle, spray onto bed bug poop, and clean. Once it’s dried you will need to vacuum it as there will be baking soda left over.


Although identifying potential bed bug poop stains is a good indicator you may have an infestation, it’s not guaranteed.

Seeing a living bed bug is the only way to truly confirm you have a problem, which can be much more difficult.

If you’re concerned, your best course of action is to contact a professional to come and inspect your home.