Mouse Traps vs Poison: Which Should You Use in an Ontario Home?

Quick answer

For a mouse problem inside an Ontario home, traps beat poison in almost every case. Traps give you a body, a count and a location — you know it worked, you know how bad it is, and you know where they are travelling. Poison gives you none of that, and a mouse that eats bait indoors usually dies in a wall void, ceiling or floor cavity, producing a smell that lasts two to three weeks and cannot be reached without cutting drywall. Rodenticides also carry real risk to pets, children and the wildlife that eats poisoned mice. Where bait belongs is in tamper-resistant, professionally placed exterior stations — not loose in a cupboard. And neither traps nor bait fixes the actual problem: the gap they are walking through.

Every fall we walk into a kitchen where someone has laid out a good-faith mix of snap traps, a tub of bait pellets under the sink and a peppermint spray on the counter — and the mice are still there. The products are not the problem. The strategy is.

Here is the straight comparison: what each method does, what it costs you in ways that never show on the receipt, and how to decide.

The short version, in a table

	Snap traps	Bait / rodenticide	Live traps	Glue boards
Confirms the kill	Yes — you see it	No	Yes	Yes
Tells you how many	Yes, countable	No	Yes	Yes
Where the animal dies	On the trap	Inside a wall, ceiling or floor	n/a	On the board
Odour risk indoors	None	High — 2–3 weeks	None	Moderate
Risk to pets & kids	Low with placement care	Highest	None	Moderate
Secondary wildlife risk	None	Real	None	None
Best used	Indoors, always	Exterior stations only	Rarely useful	Rarely justified

If you read nothing else: indoors, use traps. Reserve bait for tamper-resistant exterior stations, placed by someone who knows the label.

Why poison backfires inside a house

The appeal is obvious — bait feels like less handling than a snap trap. The problem is what happens next.

An anticoagulant rodenticide does not kill quickly. Days pass between feeding and death, and during those days the mouse behaves normally: it goes home. Home is a wall void, a ceiling cavity above a bathroom, the space under a bathtub, the insulation over a bedroom. That is where it dies, and where it stays.

What follows is a decomposition smell that peaks around days five to ten and takes two to three weeks to fade, in a spot you cannot open without cutting finished drywall. There is no spray for this, no bowl of vinegar, no ozone gadget. You wait it out or you cut. We have opened a lot of walls in Toronto and Oshawa for exactly this reason, and it is the most preventable call we take.

Then the risk profile. Rodenticides are registered pesticides, and in Canada label directions are not advice — under the Pest Control Products Act they are legally binding. Health Canada’s guidance on staying safe when using pesticides is worth reading first. Loose pellets under a sink, in a garage or in a cottage cupboard sit within reach of a dog, a toddler or a curious cat.

There is also the animal that eats the mouse. A poisoned rodent that dies outdoors, or wanders out before dying, becomes food for an owl, a fox or a neighbour’s cat, and the anticoagulant carries through. Not a fringe concern: British Columbia reviewed the evidence and made its restrictions on second-generation anticoagulants permanent. Ontario has not adopted the same restrictions, so these products remain broadly available here — which puts the judgment on the homeowner rather than the regulator.

Why traps win indoors — if you place them properly

The most common thing we see is not the wrong trap. It is six correct traps in six wrong places.

Mice are thigmotactic — a technical way of saying they hate open space and travel with a shoulder against something. A mouse crossing your kitchen runs the baseboard, the counter kick, the appliance gap. It does not stroll across the middle of the floor, which is exactly where most people put the trap.

Placement rules that change the catch rate:

• Perpendicular to the wall, trigger end touching the baseboard. The mouse runs into the trigger travelling its normal route. A trap parallel to the wall gets stepped over.
• In pairs, 15–30 cm apart, in the same runway. Mice hesitate at novel objects; a pair catches the one that dodges the first.
• Behind and under, not out in the open. Behind the stove, under the sink cabinet, along the back wall of the pantry, in the joist bays of an unfinished basement.
• Bait light and sticky. A smear of peanut butter, not a lump. A lump can be licked off without springing the trigger. Nesting material — a bit of cotton wool — often outperforms food in September, when they are building rather than only feeding.
• Leave them a few days before moving them. Constant relocation resets the mouse’s tolerance for the object.

Snap traps are the workhorse. Electronic traps work well and cost more. Live traps sound humane and mostly are not — a relocated house mouse in October has poor odds, and usually just returns or dies slowly elsewhere. Glue boards are the method we like least: indiscriminate, prone to catching non-target wildlife, and they kill by exhaustion. In a home, skip them.

The part neither method fixes

Trapping removes the mice in your house today. Bait, at best, does the same more slowly and less visibly. Neither touches the reason mice are in the house — a gap you can slide a pencil into, somewhere along a foundation, a soffit, a garage door sweep, a dryer vent or a gas-line penetration.

A house mouse passes through roughly 6 mm; a young one, less. As long as that gap is open you are not solving a problem, you are running a subscription service — killing this month’s mice so next month’s can move into the vacancy. Homeowners who trap diligently for three seasons and never seal anything are our most common repeat callers.

Placement beats product. Exclusion beats both.

Our house mouse and deer mouse identification pages cover droppings, size, colouring and behaviour. The distinction matters more than people expect — deer mice are the rural and cottage-country species, and warrant more caution when cleaning up nesting material.

When to stop doing it yourself

DIY is entirely reasonable for a small, early, ground-floor problem. Call for an inspection when:

• You are two weeks in and the catch rate is not dropping. A declining catch curve means you are winning. A flat one means they are breeding faster than you are trapping.
• There is activity in more than one area of the house. A kitchen wall and an upstairs ceiling means the stud bays are being used as a highway.
• You have found droppings on a second storey. That is an established interior run, not a scout.
• You already used bait and now there is a smell. We can locate the void and minimise the cutting.
• You have found chewed wiring or an appliance line. That is a damage-and-fire question.
• It is a rental and you are the tenant. Get it documented and reported in writing rather than self-treating.

Clean up droppings and nesting material carefully — Alberta Health Services publishes a clear seven-step guide to safe clean-up. The key points: ventilate, wet the material with disinfectant instead of sweeping or vacuuming, and wear gloves. Never dry-sweep dried rodent waste.

What a professional actually changes

Every Sani IQ service starts with a $95 professional inspection, credited when you book the treatment. What you get for it is the answer no trap can give: where they are getting in. A licensed technician maps the foundation line, roof line, garage, mechanical penetrations and interior runways, then builds the treatment around that map instead of guesswork.

Then the honest two options:

One-time is the entry point. A One-Time Mice Treatment is $345; Complete Mice Protection — the two-visit programme — is $495, with a 60-day guarantee. This clears the population you have.

The annual plan is what stops it coming back, and for most Ontario homes it is what we recommend. Mice Protection is $895/yr: monitored, tamper-resistant stations where bait belongs, scheduled visits through the season, and exclusion work maintained rather than done once and forgotten. Essentials at $1,195/yr adds general insect coverage; VIP starts at $1,395/yr.

The economics are not subtle. One serious rodent event — a chewed dishwasher supply line and the subfloor under it, a section of attic insulation, a wiring run — routinely runs into the low thousands. A year of protection is under nine hundred dollars. You are buying the absence of the event, not a stack of visits.

We cover Toronto, Mississauga, Oshawa and the wider GTA, York and Durham Regions, Simcoe County, Barrie, Orillia and Muskoka. Take the 60-second quote quiz for a real number without a phone call, or call (705) 302-1887.

Sani IQ holds a 5.0 Google rating, is BBB Accredited, carries $5M liability coverage, and is licensed under the Ontario Pesticides Act and registered with the MECP. Our technicians are employed, licensed and background-checked — never subcontractors.

Frequently asked questions

Is mouse poison or a trap better? Indoors, traps — every time. Traps confirm the kill, give you a count and a location, and never leave a carcass inside a wall. Poison kills over several days, during which the mouse returns to a wall void or ceiling to die, producing a two-to-three-week odour you cannot reach. Bait belongs in tamper-resistant exterior stations, not loose indoors.

Is rodenticide legal in Ontario? Yes. Rodenticides registered by Health Canada are available to Ontario homeowners, and label directions are legally binding under the Pest Control Products Act. British Columbia made restrictions on second-generation anticoagulants permanent; Ontario has not adopted the same restrictions, so the judgment sits with you.

What do I do if a mouse dies in my wall? Wait or cut — there is no spray that fixes it. The smell typically peaks around days five to ten and fades over two to three weeks. A technician can often narrow the location closely enough to keep the opening small if you cannot wait it out.

Where exactly should I put a snap trap? Perpendicular to the wall with the trigger end touching the baseboard, in pairs 15–30 cm apart, behind appliances and inside cabinets rather than in open floor. Bait it lightly with peanut butter or a wisp of cotton wool.

How many mice does one sighting mean? A daytime sighting usually means an established population — mice are nocturnal, so seeing one in daylight suggests competition or crowding. Droppings in more than one room point the same way.