What Do Bed Bug Droppings Look Like?

Mattress with bed bug infestation
By whitejellybeans / Shutterstock.com

It might seem surprising, but one of the easier ways to identify a bed bug infestation is through their droppings. Even though it's smaller, bed bug poop is always dark and can be easier to spot than bed bugs themselves and other typical signs of an infestation.

In Australia, as in the rest of the world, bed bug infestations are a common problem and much easier to resolve at an early stage. Learning how to identify bed bug stains will help you prevent your home from being overrun by these unpleasant pests.

How to identify bed bug droppings

You can identify bed bugs droppings by a combination of their colour, size, shape, and smell:

  • Colour - Bed bug droppings are dark in colour, varying from rusty-brown to black. Bright red or blood coloured spots are NOT bed bug droppings, though they may be a sign of an infestation. Droppings consist of digested blood, which is why the colour is dark.
  • Size - Bed bug poop is the size of a small dot - about 1 mm. On sheets, bed bug droppings look like ink spots, and they tend to appear in clusters near the location of the harbourage (that's the place where the bugs live in the daytime.)
  • Shape - Bed bug droppings are regular in shape, more or less circular. Depending on the surface, they can spread, stain, or look like tiny dark spheres. Bed bug droppings are liquid, so when deposited on an absorbent surface, they will spread. On non-absorbent surfaces, the excrements will bead up. Droppings on wooden surfaces may soak in or bead.
  • Smell - Bed bug droppings have a very distinctive, rusty odour. This is because bed bugs only eat blood. Bed bugs themselves give off a different odour - musty with hints of coriander. When you're searching for the insects, you may find that the “aroma” of the creatures is stronger than the smell of their droppings.

Do bed bug droppings smear?

When wet, bed bug droppings will smear. Once dry or absorbed, they won't smear unless, in some way, they come into contact with moisture. You can use this hack to check if a spot you're uncertain about is a bed bug dropping by doing a "bed bugs smear test":

  1. Dampen a rag or cotton bud;
  2. Apply it to the suspicious spot and rub the area carefully;
  3. If the spot smears or the rag or bud turns brown or dark red, the mark may be a bed bug dropping. If there's no smearing or colour transfer, it isn't.

Insect droppings identification and differentiating bed bug poop from that of other pests can be tricky. Cockroach droppings look similar to bed bug droppings but are generally found across a broader location, including up walls and near food storage.

Insect poop identification is helpful, but it's just one of the ways to spot pests. You have to consider other clues as well as the droppings themselves. Find out more about all of the signs of a bed bug infestation here.

Where to look for bed bug droppings

Look for bed bugs in:

  • Beds and bedding;
  • Furniture (especially second-hand furniture);
  • Carpets and fabrics.

Beds and bedding

  • Sheets - Look for clusters of spots near the edges of the bed - bed bug faeces are usually found close to their harbourages. Lines of dark red spots leading from the centre of the bed towards the edges are not droppings, however, they are also a sign of a bed bug infestation. You'll see these when a well-fed bug has crawled across the sheet back to their hiding place, dripping your blood as they go (yuch!)
  • Pillowcases - Check seams and opening flaps especially carefully.
  • Mattresses - On or around the piping of mattresses, especially at the ends and corners of the bed. Check for live bed bugs or shed skins at the same time.
  • Around the bed - Check wooden slats on all sides and on or around the headboard. Basically, you're looking for places that stay dark in the daytime and retain humidity. It's best to search with a flashlight so you can inspect hidden crevices thoroughly.


Bed bugs can live in any soft fabric, in the creases and seams of leather furniture, or on the webbing of sprung furniture. As with beds, concentrate your attention on the edges and corners - the places where the bugs can hide in the daytime.

Checking second-hand furniture before bringing it to your home could prevent you from making a costly mistake. Your bargain sofa can cost you more than a new one if it introduces the little insects to your property, and you have to hire a professional exterminator to get rid of the bed bugs.

Carpets and fabrics

Bed bugs prefer to live near their food source, but in cases of severe infestation, they can spread to just about anywhere. With that in mind, carpets near beds and around skirting boards are good places to check.

How to clean bed bug droppings

Before we get to the actual instructions, if you have an active bed bug infestation, treat it before cleaning up the droppings. Apart from saving you time and energy, this means that you can use the presence or absence of fresh bed bug droppings as an indication of whether the treatment has been fully effective.

Now, here is how to clean them:

Start by wiping using a cloth dipped in washing liquid and cold water. Bed bug stains and droppings are digested blood, so hot water will set the stain. If this doesn't work, diluted hydrogen peroxide will lift the stains. You can also try wetting the area with a baking soda and water solution. Also, note that it's essential to follow any washing or care instructions on the items you're planning to clean for guidance on the strength of the solution.

Why are bed bug droppings alarming?

Yes, they are disgusting; however, bed bug droppings aren't the most significant danger to human health. It's their bites that can cause problems.

So, how dangerous are bed bugs exactly? According to the Australian department of health and other experts, the effects of bed bug bites vary across individuals. Some people experience few or no physical impacts, and others may notice a rash and a little bit of itchiness. Bed bugs inject anticoagulants into their victims to make feeding easier. People with a high degree of sensitivity to this will experience more severe symptoms, ranging from wheals and welts on the skin right up to an anaphylactic shock, which is very rare but potentially fatal.

Bed bug bites are also vulnerable to secondary bacterial infections, and there is some emerging evidence that bed bugs may, in some instances, spread hepatitis B and MRSA bacteria.

Finally, bed bug infestations are known to affect mental health negatively. Difficulty sleeping in a once infested bed is common, and people who are uncertain if the bugs have been entirely eradicated can become anxious about every little bump they see on their skin.


  • Bed bug droppings are smaller than bed bugs but are often easier to spot;
  • Bed bug droppings can be identified by their size, shape, colour, and smell;
  • If you find bed bug poop, it's a sign that you're at risk of bed bug bites, which carry significant health risks.

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