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Stink bugs in the house: how to get rid of them
Updated 2026-11-02. Advice comes from university extension sources (read on 2026-11-02); items marked Wrenly suggestion are our own advice as a cleaning service. Prices come from our live price list. Disclosure: Wrenly Home sells house cleaning in the Peoria, IL area. We are not a pest control company.
Short answer: the stink bug in Illinois houses is usually the brown marmorated stink bug, an invasive insect that moves into buildings in September and October to spend the winter[1]. Indoors it doesn't bite people or pets, breed or damage the house[5]; warmth wakes some up in winter, so they wander into rooms[4]. Sweep or vacuum them up instead of crushing them (a shop vacuum used only for this, since a household vacuum keeps the smell[3]), or knock them into soapy water[4]. Indoor sprays are not recommended[2][6]. To prevent next fall's wave, seal cracks in late summer and early fall[2].
What they are, and why they come in
The brown marmorated stink bug (Halyomorpha halys) is native to Asia. It was first reported in the United States in 1998 in Allentown, Pennsylvania, and has since spread to more than 40 other states[1]. Illinois Extension calls it a home invader "we are starting to see more and more of in Illinois"[1], and says it is becoming a greater problem in the state each year[4]. Adults are shield-shaped, 1/2 to 3/4 inch long and mottled brown, with alternating black and white bands on the antennae and legs and smooth "shoulders"[1].
In summer it feeds on more than 300 kinds of plants, from tree fruit and vegetables to corn and soybeans[1]. Adults start looking for a place to spend the winter in September through October, often homes and other buildings[1]. They gather on the sunny sides of houses[3] and get in through gaps around windows, doors, air conditioners, vents, chimneys, soffits, siding and utility lines[3][6], and many stay hidden in wall voids and attics[6]. If you saw clusters on the outside of the house in September and October, expect some indoors later in the season[5].
How to get rid of them indoors
| Step | What to do | Source |
|---|---|---|
| Vacuum or sweep them up | Sweeping or vacuuming is the way to remove stink bugs that are already inside. Illinois Extension suggests a broom or a shop vacuum set aside for the job: a regular household vacuum can hold the smell in its filter and canister for a while. | Illinois Extension[3]; Penn State[6]; Michigan State[5] |
| Don't crush them | They release their odor when crushed or threatened, and large numbers can stain furniture with their secretions. Any secretion that gets on skin washes off. | Illinois Extension[3][2]; Michigan State[5] |
| Or knock them into soapy water | Knock or brush them into a cup or pan of mild soapy water; they can't climb out, and then they go in the trash. | Illinois Extension[4][2] |
| Skip indoor sprays and foggers | Indoor sprays are not recommended: residues work poorly, a fogger kills only the bugs in the open while more come out of the walls later, and dead bugs left in walls and attics can feed carpet beetles, rodents or cockroaches. | Illinois Extension[2][3]; Penn State[6] |
| Find where they come out | If many show up in one room, look for the gap they use: cracks under or behind baseboards, around window and door trim, and around ceiling lights and exhaust fans. Caulking those keeps them in the wall and out of the room. | Penn State[6]; Michigan State[5] |
Indoors the job is simply to keep removing the ones that appear until spring, when warmer weather sends them outside[4]. Empty the vacuum canister or bag outdoors soon after, so the bugs and their smell leave the house with it. (Wrenly suggestion)
The smell and stains
Stink bugs release their odor when threatened or crushed[2][3], and if many are crushed or vacuumed the smell can be strong; a vacuum can keep it for a while[6]. Large numbers can stain furniture through their secretions, and any secretion on skin washes off[5]. For marks that do appear:
- Painted walls, trim and furniture: blot the spot (don't rub) with a soft cloth and a little dish soap in water, rinse with a clean damp cloth, and test a hidden spot first. (Wrenly suggestion; we found no extension guidance specific to these stains)
- Curtains and washable fabric: wash as the care label says, and check the spot is gone before drying, since heat can set a stain. (Wrenly suggestion)
- Smelly vacuum: empty the canister or change the bag outdoors and wash the canister if it is washable; for a big infestation, use a shop vacuum kept for bugs, as Illinois Extension suggests[3]. (Wrenly suggestion for the cleanup)
Why they show up in winter
Overwintering stink bugs don't feed, breed or do much of anything in winter. The warmth of a heated house confuses them and delays their normal winter inactivity, which is why some crawl out into rooms and onto windows, walls and houseplants on winter days[4][2]. They don't harm people while they're there[4]. In spring the survivors try to get back outside to feed and lay eggs; eggs are laid outdoors in clusters of 20 to 30 on the undersides of leaves[1].
Keeping them out next fall
Every source agrees that keeping them out works best[3][4][5][6]. Illinois Extension says to start in early fall, before they move in[2]:
- Caulk cracks around windows, doors, siding, utility pipes and wires, behind chimneys and under the wood fascia, with good-quality silicone or silicone-latex caulk (Penn State[6]; Illinois Extension[3])
- Seal around air conditioners, air vents, chimneys and soffits, and repair or replace damaged window and door screens (Illinois Extension[3]; Penn State[6])
- Repair windows and add door sweeps (Illinois Extension[2])
- Keep outdoor lighting to a minimum, and pay most attention to the sunny sides of the house (Illinois Extension[3])
- Vinyl siding can't be fully sealed with caulk, because it is hung loosely to expand and contract; if they still get into the walls, caulk around outlet and switch plates, ceiling fixtures and heat ducts to keep them out of the rooms (Michigan State[5])
Outdoors, bugs clustered on siding can be sprayed off with a strong jet of water into a bucket of soapy water[5]. Perimeter insecticides are an option[2], but they kill only on contact and break down in sunlight within days to a week, and stink bugs can fly several miles, so one application rarely helps for long[5][6]; Penn State says exterior applications should be done by a licensed pest control operator, in fall just before the bugs gather[6]. If you use any insecticide, read and follow the label[6]. To have a bug identified, the University of Illinois Extension office serving Peoria County is at 4810 N. Sheridan Rd., Peoria (309-685-3140)[7].
Are they harmful?
To people, mostly no. They don't bite people or pets, aren't known to transmit disease and won't damage the house or reproduce in it[5]. Penn State notes two exceptions for a small number of people: those sensitive to the odor can get allergic symptoms (runny nose or irritated eyes), and crushing the bugs against bare skin can cause a skin reaction[6]. Outdoors they are a real pest of fruit, vegetables and field crops[1]. We found no extension guidance about pets eating them; if a pet eats a lot of them or seems unwell, ask your veterinarian (Wrenly suggestion).
Stink bugs vs box elder bugs
| Brown marmorated stink bug | Box elder bug | |
|---|---|---|
| Looks | Shield-shaped, 1/2 to 3/4 inch, mottled brown, white bands on the antennae[1] | About 1/2 inch, black with red or orange markings (see our box elder bug guide) |
| Smell | When threatened or crushed[2] | When crushed |
| Harm indoors | None to the house; doesn't bite people or pets[5] | None to the house; can't bite or sting |
| Removal | Sweep, shop vacuum or soapy water[3][4] | Vacuum, then soapy water |
| Outdoors | A pest of fruit, vegetables and crops[1] | Feeds on boxelder (and some maple and ash) trees without real harm |
What a Wrenly clean covers
We clean; we don't do pest control. Dead or stray stink bugs on floors and sills are vacuumed up with the dust on any visit, and a deep clean adds window tracks, blinds, vents and ceiling fans within reach of a two-step stool (see the deep cleaning checklist). We don't spray, seal entry points or work in attics, wall voids or crawl spaces. A large infestation is a job for a pest control company first; book the clean after. If something on the checklist is missed, tell us within 48 hours under our re-clean guarantee.
What it costs
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| Home | Deep clean | Then every 2 weeks (optional) |
|---|---|---|
| Studio / 1 bed (1 bath incl.) | $228 | $155 |
| 2 bed (2 baths incl.) | $272 | $189 |
| 3 bed (2 baths incl.) | $350 | $233 |
| 4 bed (3 baths incl.) | $441 | $306 |
| 5 bed (3 baths incl.) | $558 | $337 |
| Each extra bathroom | +$33 | +$20 |
Book online with your bedrooms, bathrooms and preferred day; we confirm the date by email within one business day.
Frequently asked questions
Why are there stink bugs in my house?
The brown marmorated stink bug, an invasive insect from Asia, spends summer feeding on fruit, vegetables, crops and ornamental plants. In September and October the adults look for a place to spend the winter, often houses and other buildings, and they squeeze in through gaps around windows, doors, siding, vents and utility lines. Illinois Extension says it is being seen more and more in Illinois.
Why do I see stink bugs in the house in winter?
They are overwintering in your walls and attic. Illinois Extension says they don't feed or reproduce in winter; the warmth of the house confuses them and wakes some up, so they wander into rooms and onto windows and walls. Warmer spring weather sends them back outside.
How do I get rid of stink bugs in the house?
Sweep or vacuum them up (a shop vacuum used only for this, because a household vacuum can keep the smell), or knock them into a cup of soapy water, then throw them away. Don't crush them. Indoor sprays and foggers are not recommended. To stop next fall's wave, seal cracks around windows, doors, siding, vents and utility lines in late summer or early fall.
Are stink bugs harmful to humans?
Mostly no. Michigan State Extension says they don't bite people or pets, aren't known to spread disease and don't damage houses or breed indoors. Penn State notes that some people who are sensitive to their odor can get allergic symptoms (runny nose or irritated eyes), and crushing them on bare skin can irritate it in a small percentage of people. Their secretion washes off skin.
Are stink bugs harmful to cats and dogs?
Michigan State Extension says stink bugs don't bite pets. We found no extension guidance about pets eating them, so if a pet eats a lot of them or seems unwell, call your veterinarian.
Do stink bugs lay eggs in the house?
No. Extension sources say they don't reproduce indoors. Eggs are laid outdoors on plants in late spring and summer, in clusters of 20 to 30 on the undersides of leaves.
What is the difference between stink bugs and box elder bugs?
Brown marmorated stink bugs are shield-shaped, 1/2 to 3/4 inch long and mottled brown, with white bands on the antennae. Box elder bugs are narrower, about 1/2 inch long and black with red or orange markings. Both come in for the winter and both are best vacuumed, not crushed. Stink bugs smell when disturbed; box elder bugs smell when crushed.
Does Wrenly Home get rid of stink bugs?
We clean; we don't do pest control. Dead or stray bugs on floors and sills are vacuumed up with the dust on any visit, and a deep clean also does window tracks, blinds, vents and ceiling fans within reach. We don't spray, seal entry points or work in attics or wall voids; for a large infestation call a pest control company first.
Sources
- University of Illinois Extension: Brown Marmorated Stink Bug (insect information page). https://extension.illinois.edu/insects/brown-marmorated-stink-bug. Accessed 2026-11-02.
- University of Illinois Extension, Flowers, Fruits, and Frass: Brown marmorated stink bug a nuisance to homeowners (Kelly Allsup, May 24, 2021). https://extension.illinois.edu/blogs/flowers-fruits-and-frass/2021-05-24-brown-marmorated-stink-bug-nuisance-homeowners. Accessed 2026-11-02.
- University of Illinois Extension, Good Growing: Dealing with Household Overwintering Insects: Stink bugs and flies, oh my! (Christopher Enroth, Jan 31, 2017). https://extension.illinois.edu/blogs/good-growing/2017-01-31-dealing-household-overwintering-insects-stink-bugs-and-flies-oh-my. Accessed 2026-11-02.
- University of Illinois Extension, The Garden Scoop: Unwanted wintertime house guests (Ryan Pankau, Nov 23, 2025). https://extension.illinois.edu/blogs/garden-scoop/2025-11-23-unwanted-wintertime-house-guests. Accessed 2026-11-02.
- Michigan State University Extension: Managing brown marmorated stink bugs in homes (David Lowenstein, Aug 14, 2024). https://www.canr.msu.edu/news/managing_brown_marmorated_stink_bugs_in_homes. Accessed 2026-11-02.
- Penn State Extension: Brown Marmorated Stink Bug (Steve Jacobs; revised by Michael Skvarla). https://extension.psu.edu/brown-marmorated-stink-bug. Accessed 2026-11-02.
- University of Illinois Extension, unit serving Fulton, Mason, Peoria and Tazewell Counties (offices and contacts). https://extension.illinois.edu/fmpt. Accessed 2026-11-02.
General home-care information drawn from the sources above, not pest-control, medical or veterinary advice. If you use any insecticide, read and follow the label. If anything here is out of date, email [email protected] and we'll correct it.