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University of Minnesota Extension

Bed bugs

Quick facts

  • Bed bugs bite people and feed on blood.
  • They hide and can be challenging to see.
  • They are great hitchhikers and can easily be moved by travelers.
  • If you have bed bugs, don’t panic, they can be eliminated.
  • It is very difficult to eliminate bed bugs yourself. It is best to contact a pest control service to control bed bugs.
Adult bed bug

Bed bugs (Cimex lectularius) are parasites that feed on humans, using their blood to grow and reproduce. Bed bugs also feed on animals, including dogs, cats and other pets.

People can be bitten without realizing it. Bite reactions vary from no reaction to mild (a red spot) to severe (rash or hives).

  • Reactions caused by feeding might be mistaken for other problems such as biting insects, like fleas or mosquitoes, sensitization to detergents and soaps, and irritants (e.g. poison ivy).
  • It is not possible to verify bed bugs from only red skin lesions; finding bed bugs is the only way to confirm they are present.
  • Bed bugs are not known to transmit disease to people.

Bed bugs are found in many places, including homes, schools, retail facilities, office buildings, libraries and other public areas.

Bed bugs were almost completely removed from North America due to mass treatments with highly toxic insecticides that are no longer in use. Frequent travel, being good hitchhikers, improved treatment methods that target other insects without affecting bed bugs, and a lack of public awareness has led to a rise in the spread of bed bugs.

Identifying bed bugs

Bed bug before a meal
Bed bug after a blood meal

Be sure you have bed bugs before trying to control them. Research at the University of Minnesota found that 76 percent of samples submitted for identification are not bed bugs.

  • Adult bed bugs are oval, flattened, brown and wingless insects approximately 1/4 to 3/8 inch long (5-9 mm). They are similar in appearance to a wood tick.
  • After the bug has taken a blood meal its color changes from brown to purplish-red and becomes larger and more cigar-shaped.
  • Young bed bugs resemble adults in shape but are much smaller, 1/16 inch (1.6 mm) when they first hatch. They are nearly colorless except after feeding.

Contact an expert to help identify any suspected bed bug specimens.


Signs that you have bed bugs

Look where you sleep

Bed bugs typically group together in out-of-the-way areas, although some bed bugs will live by themselves, away from the rest of an infestation. The best way to check for an infestation is to look for bed bugs where you sleep or rest.

In bedrooms, look particularly on and around:

  • Box springs, mattresses, bed frames, tufts, folds and buttons on mattresses.
  • Furniture such as desks and chairs.
  • Behind wallpaper, clocks and pictures.
  • Cracks in wood floors and under the edge of carpet.

While bed bugs are most commonly found in bedrooms, infestations can occur in other rooms including bathrooms, living rooms and laundry rooms.

Bed bugs on a metal bed frame
Bed bugs on the underside of a box spring
Bed bugs along a mattress seam

Look for spots or smears 

Bed bugs will sometimes deposit fecal spots (digested blood) while they are feeding. These are seen as dark (dark reddish or brownish) spots or smears found on bed sheets, pillowcases and mattresses, or in nearby areas.

  • Dark blood spots on sheets and bedding may indicate bed bug feeding.
  • In severe infestations, bed bugs may be more noticeable.
  • A combination of bed bugs, cast skins (empty shells of bugs as they grow from one stage to the next) and fecal spots will be very obvious when closely seen.
Bed bug nest

Inspect carefully

These insects are small and very flat, so they can move into very tight corners and cracks. They have been found under picture frames between the glass and the frame.

Bed bugs can be found behind electrical outlets and other wall plates.

  • Inspect all areas closely and, if in doubt, contact a pest control service.
  • If you find a bed bug stop inspection and begin control activity.
  • Bed bugs will move from their hiding places once disturbed. All further inspections should be accompanied by control measures.

How to avoid bringing bed bugs into your home

Video: How to prevent bed bugs from entering your home (02:17)


How to get rid of bed bugs


Authors: Jeffrey Hahn and Stephen Kells, Extension entomologists

Reviewed in 2023

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