What Do Bed Bug Feces Look Like?

Why would anyone in their right mind go looking for the poop? Although, looking for bed bug poop could be useful. Finding bed bug poop is the most effective way to tell if you have an infestation without seeing a bug.

Where there are feces, there has to be a bed bug – and usually, there’s not just one, there’s a lot.

Here’s what you need to know about what bed bug feces look like.

How Do You Identify Bed Bug Poop?

Easily. But first get torched up and gloved up to look for the dirt. You’ll know you’ve found the poop you’re looking for by finding stains with three simple properties.

  • 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.  
  • 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.
  • 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. 

You’ll often notice bed bug feces with thin, black streaks. Bed bugs excrete as they are crawling. This works well, since they prefer to be on the move. It’s a bed bug survival instinct. Stopping to poop leaves anybody vulnerable. When checking for bed bugs, streaky poop is as good as a calling card. 

Not sure if that streak, spot or smudge is indeed bed bug poop? There’s an easy way to tell

Simply take a wet paper towel and dab at a spot. Bed bug fecal matter will smudge red onto the towel when wet. It’s useful to know right away and nowadays, there’s a lot of other useful bits of information about bed bugs including images their feces on the internet to help with a quick double check. 

Fact: All life stages of bed bugs – from nymphs to adults – rely on a blood meal, except for the egg, and it’s possible for them to get a meal from other bed bugs.

Will You Find Bed Bug feces on Your Sheets?

Yes, it’s possible to find bug poop in your bed but the chances are lower. These pests feed and return to their hideouts to digest the meal. It usually takes several days, and there won’t be any dropping or feeding until they have finished digesting.

This means that when you are looking for evidence of infestation, you need to look further than in your bed. You need to search carefully around and under the mattress especially along its seams, and along the bed frame.

Since bed bugs climb so well, check out the walls particularly behind peeling wallpaper, along the skirting boards and even behind picture frames. It’s only in the case of a heavy infestation you’ll wake up to notice tell tale dot-like feces around you.

Depending on the level of infestation, you might even have to hunt a little bit. Bed bugs hide and hang out in any crevices and there will be feces nearby. Sometimes, you can follow it back to the hideout like a trail. You might come across eggs or broken egg casings on the way. These are like very small grains of rice.

Do Bug Feces Stink?

There’s one small mercy but it’s tiny. Unlike the feces of other animals, bed bug droppings don’t really smell bad. Even so, you might notice a slight aroma or rusty taste in the air when you come into the room. To be blunt but this is good search motivation. That’s your blood in their poo drying out.

Although bed bug feces won’t stink as such, there is still a strong smell around favorite bed bug points of harborage. These insects continuously lay down and follow chemical scent trails. If you like, although it’s not urine that’s secreted, they pee on the go, like rats whose astringent odor make your eyes water.

With bed bugs the odor is sweeter, earthy and musty not unlike the smell of fresh coriander.  

Can It Cause Any 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 problems 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.


It’s easy to confuse bed bug droppings with dirt, but you should always be vigilant. The earlier you identify an infestation, the easier it’s to deal with. You are looking for bug digested blood basically – your blood, and that’s pooped out for you to clean up in a neatly consistent shape, color and size.

Andrew Cunningham
Andrew Cunningham
Hello, Andrew is the co-founder and lead editor for DailyPest.

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