How to Kill Mice: What Actually Works (and What Doesn't)

The most reliable way to kill mice is snap traps — set correctly, in the right locations, with enough of them. Everything else is either slower, more expensive, riskier, or doesn't work at all. Here's an honest breakdown of every method.

Key facts:

Snap traps are consistently the most effective and cost-efficient removal method
Poison does not address entry points — new mice replace poisoned ones within days
A poisoned mouse typically dies inside walls, not where you can find it
The FTC has warned companies making unverified efficacy claims for ultrasonic repellers¹
Peppermint oil and ultrasonic devices are not effective at eliminating an active infestation

Snap Traps

The standard. Snap traps are fast, cheap, reusable, and consistently outperform every other method in independent testing. The Victor Easy Set is the most widely used and works well. Victor Easy Set snap traps →

How to use them correctly:

Place the trap perpendicular to the wall, trigger end toward the baseboard. Mice run along walls; a trap placed parallel to the wall is easier to trip without getting caught.
Bait with peanut butter — a pea-sized amount pressed into the trigger. Cheese is a myth; peanut butter sticks and smells better to a mouse.
Use more than you think you need. In an active kitchen, six to eight traps placed along different walls is a reasonable starting point. Mice are cautious and may avoid one trap but encounter another.
Check daily. A dead mouse left for days reduces trap effectiveness and creates cleanup issues.
Wear gloves when handling traps and disposing of mice.

Where to place them: under the stove, behind the refrigerator, inside lower cabinets, along basement walls, behind the washer/dryer. Full trap placement guide →

Electric Traps

Electric traps deliver a high-voltage shock that kills instantly. They're more expensive upfront (around $25–$40 per trap) but cleaner — no blood, the mouse is contained inside the trap. Good option if you're squeamish about snap traps or need to set traps in visible areas.

Victor Electronic Mouse Trap →

The kill rate per catch is the same as snap traps. The main downsides: cost, and they require batteries.

Poison Bait Stations

Rodenticide blocks placed inside tamper-resistant bait stations. Mice eat the bait, return to the nest, and die within a few days. They work, but come with significant drawbacks:

The risks:

Pets and children — anticoagulant rodenticides are toxic to dogs, cats, and children if ingested. Tamper-resistant stations reduce but don't eliminate this risk indoors.
Secondary poisoning — a mouse that eats rodenticide and dies outside can poison the hawk, owl, or cat that eats it. The EPA documents this as a significant ecological concern with first- and second-generation anticoagulant rodenticides.²
No body to find. Mice typically die inside walls or other inaccessible spaces, leaving you with a decomposing mouse you can't locate. Dead mouse smell →
They don't work faster than traps — often slower, since mice need multiple feedings.

Bait stations make more sense in exterior perimeter use (garages, crawl spaces, exterior foundation) than inside living areas. If you have pets or children indoors, snap or electric traps are the safer choice.

Rodenticide bait stations (exterior use) →

CO2 Traps

CO2 traps (like the Goodnature A18) kill with a quick burst of compressed gas — considered the most humane mechanical kill method. They're expensive ($100+), require CO2 cartridge refills, and are typically used in commercial or farm settings. They work, but the cost is hard to justify for a standard home infestation.

What Doesn't Work

Glue traps — these catch mice alive but don't kill them. The mouse panics and suffers for hours or days until it dies of stress, exhaustion, or dehydration. Most pest control professionals recommend against them. They also catch non-target animals including lizards, birds, and small pets. Skip these.

Peppermint oil — mice may avoid a location that smells strongly of peppermint oil initially, but they habituate quickly. No field data supports peppermint oil as an effective deterrent, and it does nothing to eliminate mice already present.

Ultrasonic repellers — the Federal Trade Commission has taken action against companies making unsupported efficacy claims for ultrasonic rodent repellers.¹ Multiple studies show mice habituate to the sound within days. Don't spend money on these.

"Natural" predator scents — fox urine, cat litter near mouse paths. May provide minor deterrence in controlled conditions; not reliable in a real infestation.

Method Comparison

| Method | Effectiveness | Cost | Safe with pets/kids | Notes | |--------|--------------|------|---------------------|-------| | Snap traps | High | Low | Yes (placed carefully) | Best overall choice | | Electric traps | High | Medium | Yes | Cleaner, more expensive | | Bait stations | Medium-High | Medium | Risk indoors | Better for exterior use | | CO2 traps | High | Very high | Yes | Commercial/farm use | | Glue traps | Medium | Low | No | Inhumane; not recommended | | Peppermint oil | None | Low | Yes | Does not work | | Ultrasonic devices | None | Low-medium | Yes | Does not work |

Safety With Pets and Children

Snap traps placed under appliances, inside cabinets, or behind furniture — areas a child or pet can't easily reach — are the safest indoor method. If you have small children or pets that get into everything:

Use covered snap traps (enclosed housing, trigger inside) — the mouse enters but a child or pet cannot easily trip the mechanism
Use electric traps, which contain the mouse inside
If you use bait stations, place them only in locations completely inaccessible to pets and children (inside wall voids, in crawl spaces, in exterior bait boxes)

The Bigger Picture

Killing mice only solves the problem temporarily if entry points aren't sealed. New mice from outside will replace the ones you remove. The Seal-Trap-Clean sequence — seal first, trap second, clean third — is the approach that resolves infestations permanently rather than just reducing them temporarily.

How to get rid of mice (full guide) →

How to seal entry points →

Connect with a local pest control expert →

Sources

Federal Trade Commission. "FTC Warns Marketers of 'Pest Control' Devices." ftc.gov — Guidance and warning letters to companies making unverified efficacy claims for ultrasonic pest control devices.
U.S. Environmental Protection Agency. "Rodenticides." epa.gov/rodenticides — Secondary poisoning risks from first- and second-generation anticoagulant rodenticides.