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Mus musculus
Updated Mar 29, 2023

Make a Positive Identification

Mice (house mouse) (Mus musculus) are small, non-native rodents found in homes and structures. They use space in walls and openings around pipes to move inside structures.

Species: Mice
Mouse example

Ed Freytag, City of New Orleans,

Mice are small, non-native rodents found in homes and structures. Adult mice grow to about 5–7 inches long, including the tail.

Species: Mice
Mouse fecal pellets on white trim in home

Liz Kasameyer, Johns Hopkins School of Public Health,

Look for feces and urine on floors and under furniture and appliances. Mouse urine is smelly. Black fecal pellets have pointed ends from 1/8–1/4 of an inch long.

Species: Mice
Mice damaged a wall and left many fecal pellets on floor

Liz Kasameyer, Johns Hopkins School of Public Health,

Mice damage buildings. Their urine and feces are health hazards.

Look-Alikes: Voles & Rats
Species: Voles
Vole tunnels in grass

David L. Clement, University of Maryland,

Voles are native species of mice. They live and prosper in grassland and similar settings, such as lawns. The burrowing shown above is a sign of vole activity in a grassy area. They generally don’t damage structures.

Different risks or methods

Mow grassy areas to limit vole habitat.

Voles will gnaw on the bark at the base of trees and shrubs. Protect new plantings of fruit trees and restoration plants with plastic guards to exclude voles.

See Meadow Voles & Pocket Gophers  (OSU Extension Service) for more information.

Species: Rats
Rat in building with apple slice

Ed Freytag, City of New Orleans,

Adult rats (Rattus spp.) are much larger than mice (house mouse) and voles. Rats are non-native, invasive species. They spread diseases, damage structures, and ruin stored goods.

Different risks or methods

Take action to control rats in your home and structures. Remove food sources and habitat. Seal structures to keep them out. Control existing populations. Monitor for rat activity and take action as needed.

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Mice Benefits

  • House mice (Mus musculus) are non-native and invasive in North America.
  • They don’t have any benefits for people and the environment.
  • Deer mice (Peromyscus spp.) are native, but also pose some risks to humans.

Mice Risks

  • Mice are a health threat to adults, children, and pets.
  • Their gnawing, nest building, and excessive feces and urine cause property damage.
  • They chew through boxes and plastic bags to get to food and nest areas. Mice ruin stored food and belongings.
  • Mice populations build quickly. A single female mouse has 5–10 litters each year. Each litter has 5–6 young. Female mice reach sexual maturity in 5–7 weeks.
Human diseases such as salmonellosis and leptospirosis can be transferred to humans via contact with mouse feces. Dried urine and feces particles in the air can trigger asthma. Hanta virus, though rare in the Pacific Northwest, can be passed by inhaled deer mouse feces.
Risk Card
Does it cause harm?
Adults & Children
Action Highly Recommended


Take action right away if you find mouse damage in your home or belongings. Mice are a health threat for adults, children, and pets.

Do I need to take action?
Yes. Don’t tolerate mice in your home or storage areas.

What if I do nothing?
Once mice get into your home or storage area, they will multiply quickly. They make a mess and are a human health threat.


Consider a licensed pest control company. Learn How to Hire a Pest Control Company.
Your local Extension Specialist in Oregon  and other states  can suggest other methods.

Solutions for Mice

Remove Food Sources and Exclude Rodents

  • Start by removing any food sources like trash access, bird seed, pet food, or compost. Sanitation must be ongoing.
  • Rodent-proof your home and buildings to exclude them. Fix holes and seal gaps. Use welded wire “hardware cloth” with ¼-inch openings to exclude mice. Use copper or steel wool around pipes and cables.
  • Consider hiring a pest control company or a contractor familiar with rodent-proof construction and exclusion methods. See How to Hire a Pest Control Company for details.

Clean Up Rodent Messes

  • See health and safety tips to minimize risks from cleaning activities.
  • Clean up rodent feces, urine, and damaged items. Use gloves. Spray with a disinfectant before handling mice damage. Wear a dust mask with a HEPA filter. Inhalation of dust from dried urine and feces is where many health problems start.

Control Mice Populations

  • Get rid of mice using the trapping methods described below. Trapping is a good first choice.
  • Carefully consider using toxic bait products (rodenticides). Use a bait station to reduce the risk of poisoning to children, pets, and wildlife by limiting access. Never leave loose bait unattended.

Jump To

Method Does it work? Is it safe? Recommendation
Remove Food Sources & Repair Structures
Very effective
Moderate risk
Moderate risk
Rodenticides (Toxic Baits)
High risk
Use if Necessary
If Using Rodenticides, Protect Yourself & Minimize Risks
Prevent Mice

Remove Food Sources & Repair Structures

Non-Chemical Method

FalconScallagrim, iStock

Remove Food Sources & Repair Structures

Before you set traps or use toxic bait, you need to remove food sources and mouse-proof your building. Otherwise, mice will return.

Does it work?
Very effective

These steps are required for successful control of mice in home and structures.

How much effort?
High effort

Remove food sources for rodents. Use good carpentry practices and sealing techniques to close off entry points.

What's the risk?
Moderate risk

See health and safety tips to minimize risks from sanitation and mouse-proofing activities.

Possible risk of exposure or harm from chemicals

Removal of food sources and rodent-proofing your structures are key steps to get rid of mice. After you perform these steps, then use trapping and/or toxic baits to kill an existing population of rodents.

Mouse eating food in dark area

FalconScallagrim, iStock

Remove Food Sources (Sanitation)

  • Removing available food is critical to mouse control and must be continuous.
  • Don’t leave pet food, chicken feed, or wild bird seed in a place where rodents can get to it.
  • Keep pet food stored in thick plastic or metal bins.
  • Don’t leave food out on kitchen counters.
  • Use mouse-proof food compost systems.
  • Clean up fallen fruits and vegetables from orchard and garden areas.
  • Keep garbage in a plastic or metal bin with a tight lid.
Rat entry point through gap under garage door

Liz Kasameyer, Johns Hopkins School of Public Health,

Rodent Proofing & Rodent Exclusion

  • Thin or remove plant growth near buildings that provide hiding cover for rodents and their nesting sites.
  • Protect chicken coops with ¼-inch hole aviary wire or hardware wire. Bury the wire below ground. Close any holes bigger than a nickel.
  • Repair holes and gaps larger than ¼ inch around doors, windows, crawl space screens, attic vents, and all other building exterior access points.
  • Mice tend to use existing holes and aren’t very effective at gnawing holes. By comparison, rats are able to gnaw holes.
  • Close gaps around utility service entries such as plumbing pipes by using un-chewable welded wire or steel/copper wool.
  • Securely cover chimneys with a spark arrester.
  • Make sure all exterior doors are tight fitting and weatherproofed at the bottom.


Non-Chemical Method

Weston Miller, Oregon State University


Trapping is an effective way to reduce the population of mice. It is a good first choice. Follow the directions below for best results.

Does it work?

Trapping effectively gets rid of mice when used with preventive measures. You must also remove food sources and exclude rodents from the structure to get rid of them successfully.

How much effort?
High effort

You must set multiple traps and reset them daily until you no longer see fresh signs of rodent activity.

What's the risk?
Moderate risk
  • While setting and cleaning used mouse traps, you can be exposed to diseases mice carry. See health & safety tips.
  • Spring-loaded traps can harm children, pets, or wildlife if used improperly. Think carefully about where you place the traps.
Possible risk of exposure or harm from chemicals

Set multiple traps and use the prebaiting method. Be persistent in your mice-trapping efforts.

Correctly set mouse trap with the bait end against wall

Weston Miller, Oregon State University

Place traps along a wall with the trigger end against the wall. Put them at a right angle to the wall to intercept, rather than block, rodents’ travel.

Multiple mouse traps placed along walls

Weston Miller, Oregon State University

Set multiple traps placed in corners, along walls, and behind boxes.

Mouse-Trapping TIps

  • Mice rarely figure out traps and avoid them. In fact, they tend to prefer traps that have captured other mice.
  • Check traps daily or more often when you are dealing with a large population. Rats do figure out traps.

How to Set Mouse Traps

  • Plastic snap traps are easy to set and disinfect.
  • Nuts, peanut butter, cheese, dried fruit, and pet food are good baits.
  • Fasten solid bait securely to the trap trigger with a fine wire.
  • Set traps so the trigger will spring easily.
  • Place traps where mice travel so they will pass directly over the trigger of the trap; for example, along walls, behind boxes, and under equipment and furniture. Look for mice droppings and gnaw damage, and install traps there.
  • Check traps every 24 hours.
  • Remove and dispose of captured mice and reset the traps. Wear disposable gloves or rubber gloves that can be disinfected.

Prebait, Move Traps & Reset Method

  • Prebait the traps by baiting and placing them without setting them to snap. After 2–3 days, rebait the traps and then set them.
  • This process encourages the mice to ignore the traps. It makes your trapping more effective once you do set the triggers.
  • If you don’t trap mice after 2–3 days, remove the traps and stop using them for several days.
  • Move the traps to a new spot 5–10 feet away. Prebait and then set the traps.
  • Repeat the sequence until you get rid of all the mice. 

Other Trap Options Have Disadvantages

Battery Traps

  • Battery-operated electrocution traps have been shown to provide good control of mice.
  • They are considerably more expensive than snap traps.

Live Traps

  • Live catch traps are boxes that have an entrance but no exit, and do not injure mice. However, trapped mice may be noisy as they try to escape. When you use these traps, mice have to be removed and humanely euthanized with a strong blow to the head. Drowning is considered inhumane. Releasing live mice caught in the traps won’t solve your rodent problem.
  • Glue boards are pieces of flat cardboard with a thick layer of glue on one side, similar to fly paper. Mice don’t die quickly and struggle to get free. If you find a live mouse in a glue board, it needs to be immediately and humanely euthanized with a strong blow to the head.
A live mouse trapped in a glue trap


Glue boards don’t kill rodents right away. If you find a live rodent in a trap, you must humanely euthanize it.


Rodenticides (Toxic Baits)

Chemical Method: Use with caution

Weston Miller, Oregon State University

Rodenticides (Toxic Baits)

Use if Necessary
  • Rodenticides effectively control mice populations when used according to label directions.
  • Use rodent bait stations to minimize access of the toxic bait for people, pets, and wildlife.
Does it work?
  • Toxic baits are effective when used with preventive measures.
  • You must also remove food sources and exclude rodents from the structure to get rid of them successfully.
How much effort?
Moderate effort

Many rodenticide product labels recommend maintaining fresh bait in bait stations until there are no longer signs of new rodent activity.

What's the risk?
High risk
  • Using toxic baits comes with real risks. ALWAYS read the entire label front to back. Review instructions even for brands you know.
  • Mice baited with toxic bait can die inside walls and crawl spaces. Decomposing mice bodies smell bad and create a human health hazard.
  • Rodenticides are toxic to children, pets, and wildlife.
  • If used according to the instructions, bait stations are “Child & Dog Resistant,” as stated in the white box on the example product label above.
Possible risk of exposure or harm from chemicals
Using rodenticides includes some amount of risk. The lowest risk comes with using alternative methods.

You may be exposed to a rodenticide if you:

  • Get it on your skin
  • Breathe it in
  • Eat or smoke afterward without washing hands
  • Bring it inside on your shoes or clothes

Follow directions closely to reduce risk.

It is critically important that you follow rodenticide product directions to properly and legally place stations inside buildings or near the building perimeter.

Bait station for mice in corner

Liz Kasameyer, Johns Hopkins School of Public Health,

  • If you choose to use rodenticide products, make sure to use bait stations to exclude children, pets, and wildlife from the toxic bait.
  • Never leave unsecured bait unattended.

Rodenticide Active Ingredients

Warfarin, chlorophacinone, diphacinone and cholecalciferol are common active ingredients in rodenticide products for use in homes and structures.

Application Tips

  • Place bait in tamper-proof bait stations that limit access to the toxic bait.
  • Poisoned rodents sometimes die in hard-to-reach places, decay in place, and then smell bad and create a new health hazard.
  • Collect and dispose of any dead rodents. See health & safety tips.
  • Bait products require several days to kill rodents.
  • Ensure the stations are continuously supplied with bait. Replace moldy or damaged bait.

Remove Food Sources and Repair Structures BEFORE Using Toxic Baits

  • If you don’t remove food sources and secure your buildings, toxic baits won’t get rid of rodents.
  • You’ll need to keep using poison bait repeatedly.
  • If you can’t block access or remove rodent nesting areas, ongoing baiting might be necessary.

If Using Rodenticides, Protect Yourself & Minimize Risks

Chemical Method: Use with Caution
Dog and cat in house

chendongshan, iStock

Rodenticides are extremely toxic to humans, pets, and wildlife. Baits are made to attract animals with tasty smells and flavors. Pets and wildlife can be poisoned if they eat rodents that consume rodenticides.


Why Is It Important to Read Rodenticide Labels?

  • They have detailed information on how to use the product correctly and legally.
  • They contain information about specific rodent species, their habits, and control methods.
  • They provide information on potential hazards of the product. They have instructions you should follow for poisonings and spills.

The Label is the Law

ALWAYS read the label before using rodenticide products. The label is a legal document that provides information on how to safely use the rodenticide. This helps avoid harm to human health and the environment. Using a rondenticide in off-label ways is illegal. It can result in legal enforcement actions.

READ THE LABEL & Follow Instructions
It has instructions to protect you and the environment.

  • Labels are different for every product and they often change over time.
  • Use a magnifying glass.
  • Pay attention to CAUTION, WARNING, and DANGER statements.
  • Pay attention to the PRECAUTIONARY STATEMENTS.
  • The law states you must read and follow rodenticide instructions.

Protect Children, Pets, Domestic Animals & Wildlife
Children, pets, and wildlife are at risk if they touch or consume poison toxic bait for rodents.

  • Keep rodenticides out of reach from children and pets at all times.
  • Dogs, cats, and wildlife are also attracted to and harmed by rodenticides.
  • Use bait stations to protect children, pets, and wildlife.
  • Rodenticides may be gathered by mice or rats and cached for later use. The cache location may not be safe for pets or children.
  • Dogs, cats, and wildlife can be poisoned if they feed upon rats that have eaten rodenticide.

Protect Yourself
Eye, skin & lung irritants

  • Wear gloves and safety glasses when handling rodenticides.
  • Avoid contact with eyes, skin, or clothing.

Storage & Disposal

  • Store out of the reach of children and pets.
  • Follow the label instructions for disposal of rodenticide products.

Call  1-800-CLEANUP (1-800-253-2687) to find out where to dispose of pesticides.

For the Portland metro region in Oregon, contact Metro’s Recycling Information. Call  503-234-3000, email   or visit Metro’s website  

More about:

About Using Pesticides on School Grounds in Oregon

If using pesticides on school grounds, there are special rules in Oregon. See School Integrated Pest Management  (Oregon Department of Agriculture).


The National Pesticide Information Center (NPIC)  can answer questions about pest control chemicals.
 1-800-858-7378 or  

Consider using a licensed pest or weed control company. Learn How to Hire a Pest Control Company.

Your local Extension Specialist in Oregon  and other states  can suggest other methods.


Prevent Mice

Trash, yard debris, and recycling bins with sturdy lids

Weston Miller, Oregon State University

Use Trashcans with Secure Lids

Make sure your trashcan excludes all rodents and clean it from time to time.

Open trash can with food and debris

Gary Alpert, Harvard University,

Don’t Leave Trash Exposed

Don’t overfill trash cans and provide a food source for rodents.

Rigid plastic container for pet food

Weston Miller, Oregon State University

Store Pet Food and Bird Seed in Robust Containers

Exclude rodents from bird seed and pet food by using containers made of thick plastic or metal and a secure lid.

Food scraps

Weston Miller, Oregon State University

Don’t Attract Rodents with Food Scraps in Your Compost
  • If you compost food scraps at home, use a rodent-proof composting system.
  • If your compost area is not rodent-proof, avoid including meat, milk, and bread products that won’t break down quickly. Keep mixing and maintaining the pile so heat stays high and breaks materials down fast.
Door sweep and threshold

Weston Miller, Oregon State University

Use Door Sweeps

Install door sweeps that seal the gap between the threshold and the door base.

Pipes through floor with gap allows rodent entry

Gary Alpert, Harvard University,

Use Good Carpentry Practices
  • Seal around water, gas, water service pipes, and conduit installed in walls and floors.
  • The space between the pipes allows access for mice. Use good carpentry practices and sealing techniques to close off entry points.
Hole in foundation showing rodent entry point

Gary Alpert, Harvard University,

Seal Gaps in Construction
  • Fill entry points as small as a dime with sealant and/or steel or copper wool.
  • Larger holes similar to the hole in the building foundation shown in the photo need to be filled with concrete.
Dryer vent with proper screen to prevent rodent entry

Liz Kasameyer, Johns Hopkins School of Public Health,

Seal Exterior Vents
  • Maintain and repair all building ventilation screens, louvers in attic spaces, and furnace closet doors and vents.
  • Any gaps around the screen frames and louvers require sealing.
Shelving pulled back to expose wall with exposed studs for rodent monitoring

Weston Miller, Oregon State University

Declutter and Check for Signs of Rodents
  • Declutter storage spaces to eliminate places rodents can hide. Pull boxes and items away from walls and shelves as shown in the photo.
  • Monitor for rodent activity. Clean the area as needed.


Use disposable or rubber gloves to clean up dead rodents and their feces, urine, and nests.

Wear a dust mask with a HEPA filter when cleaning an area with excessive rodent droppings and damage.

Don’t use a broom or vacuum. These actions may cause the viruses and bacteria living on the rodent droppings to become airborne. Inhaling those could make you sick.


  • Wet the stained or damaged area with a disinfectant. Disinfectants such as 10 percent bleach/water solution will kill disease-causing bacteria and virus.
  • Apply a disinfectant and wait ten minutes. Use a moist cloth or paper towel to wipe up the droppings and mouse damage.
  • Put all of the waste, including your disposable gloves, in a trash bag. Dispose of it right away.
  • If you use a washable cloth and reusable gloves, clean those items in soapy water and disinfectant.
Gloved hand cleaning rodent debris

Liz Kasameyer, Johns Hopkins School of Public Health,

Content provided by editor Weston Miller and writer J. Jeremiah Mann. Vertebrate information edited by Dana Sanchez. Pesticide safety information edited by Kaci Buhl.

 Peer reviewed by OSU Department of Horticulture.

Photo of Weston Miller

Weston Miller

Project Founder and Content Writer

Weston Miller served as Community and Urban Horticulture faculty for Oregon State University Extension Service for Clackamas, Multnomah, and Washington Counties. Weston is an author for content for this website. He developed funding partnerships with Portland area agencies to initiate and build out the Solve Pest Problems website focused on this goals:

J. Jeremiah Mann

J. Jeremiah Mann

J. Jeremiah Mann completed a Physical Science undergraduate degree at Humboldt State University, and M.S, Ph.D focusing on plant science topics at UC Davis. He went on to work for the Natural Resources Conservation Service and in a leadership position serving a private agricultural technology company. He currently lives in Sacramento California where he consults on pest and property management topics.

Photo of Dana Sanchez

Dana Sanchez

Dr. Dana Sanchez, Extension Wildlife Specialist, addresses wildlife-related questions on Ask Extension and produces Extension publications, webinars, and presentations to groups such as Master Gardeners. She also conducts research on native mammal species of the West in collaboration with her graduate students and undergraduate research interns.

Photo of Kaci Buhl

Kaci Buhl

At the state level, I lead the Pesticide Safety Education Program (PSEP). The program hosts live recertification events around the state, serving over 1,000 licensed pesticide applicators each year. We also produce web-based training modules and license-preparation study manuals. Special training for unlicensed pesticide applicators is also available through a grant from the USDA Specialty Crop Block Grant Program. The PSEP at OSU works closely with the Oregon Department of Agriculture's Pesticides Division.