Rat poison, slug pellets, antifreeze: garage poisons and dogs
Published by Planète Pets · managing editor: Clément Lacaille · how our guides are written
If you think your dog has swallowed rat poison, slug pellets or antifreeze (engine coolant), do not wait for it to fall ill: call your vet or the emergency vet straight away, or an animal poison helpline — in the US the ASPCA Animal Poison Control Center, (888) 426-4435 (a consultation fee may apply), in the UK Animal PoisonLine, 01202 509 000, in France the CNITV in Lyon, 04 78 87 10 40. Keep the packaging or photograph it: the name of the active ingredient changes the whole treatment. Do not make your dog vomit yourself and do not give milk or salt: that is the vet’s call. These three products share a misleading feature: a dog that seems fine right afterwards is not out of danger, either because signs come very fast or because they come days later.
Contents · 6 sections
Three poisons, three different clocks
What makes these products dangerous is not just their toxicity but their timing. The table below sums up, for each one, when signs appear and why you need to act fast. Timings come from the Merck Veterinary Manual, the vets’ reference, and from the studies cited below.
| Product | Where it is found | First signs | Why call straight away |
|---|---|---|---|
| Anticoagulant rat poisons (bromadiolone, difenacoum, brodifacoum…) | Bait blocks, pastes, grain; garage, cellar, garden shed | Bleeding 3 to 7 days after ingestion; clotting affected from 2 to 5 days | An antidote exists and the vet can act before any bleeding; waiting for signs throws that head start away |
| Metaldehyde slug pellets | Blue or green pellets in the vegetable patch, opened bags | Trembling, agitation, high temperature, seizures between 30 minutes and 6 hours | It progresses fast; early treatment often allows full recovery |
| Ethylene glycol antifreeze | Engine coolant, containers in the garage, puddles under a car | Drunken gait, vomiting, thirst between 30 minutes and 12 hours, then a misleading improvement; kidney damage 36 to 72 hours later | Treatment only really works before the kidneys are affected, in the first hours |
Anticoagulant rat poisons: the danger that waits
Most household rat poisons stop blood from clotting. The dog shows nothing for several days, while its stock of clotting factors runs down. Then come tiredness, breathlessness, pale gums, nose or gum bleeds, blood in the urine or black stools, unexplained bruising. A study by Stroope and colleagues, published in 2022 in Frontiers in Veterinary Science, described 62 dogs treated for bleeding caused by these products at two US university veterinary hospitals (see the study): the most common bleeding site was the chest cavity (37%), followed by the lungs (24%) and the abdomen (24%) — places you cannot see from the outside. More than half the dogs were bleeding in several places. That is why a dog that has got into bait should be seen before it has signs: the vet can check clotting and give the antidote, vitamin K1, for as long as needed. Note that not all rat poisons are anticoagulants, which is why the packaging matters.
Metaldehyde slug pellets: the danger that runs
Metaldehyde acts on the nervous system. A study by Bates and colleagues, published in 2012 in the Veterinary Record, analysed 772 calls about dogs to the UK Veterinary Poisons Information Service between 1985 and 2010 (see the study). Half the cases happened in summer; 77.3% of dogs developed signs (seizures, drooling, twitching, oversensitivity, tremors, vomiting, high temperature), on average 2.9 hours after ingestion, and half within the first hour. Overall, 16% of the dogs died or were euthanised. Pellets based on ferric phosphate are presented as less toxic, but eating a large amount still warrants a call. In the UK, outdoor use of metaldehyde slug pellets has been banned since 2022, but old stock may still be around in sheds.
Antifreeze: the danger that hides
Ethylene glycol tastes sweet, according to the Merck Veterinary Manual, and in cold climates poisonings are more common in autumn, winter and early spring, when cooling systems are topped up or flushed. A small amount is enough to be dangerous, and cats are even more sensitive than dogs. After a phase in which the dog seems drunk, it may appear to improve while kidney damage is building up. A study by Connally and colleagues, published in 1996 in the Journal of the American Veterinary Medical Association, followed dogs treated with an antidote at Colorado State University (see the study): of the 37 confirmed poisonings, all 16 dogs treated before the kidneys were affected survived, against 1 in 21 once kidney damage had set in. Dogs treated within 8 hours of ingestion had a good prognosis.
Store things so you never have to call
- Rat poison: prefer mechanical traps or a professional; if you use bait, only in locked tamper-resistant boxes, out of reach, and note where and which product.
- Slug pellets: keep the bag closed and up high; in the vegetable patch, prefer physical barriers and hand-picking; never scatter pellets where your dog walks.
- Antifreeze: capped containers on a high shelf or in a closed cupboard, funnels and rags thrown away, spills mopped up immediately, and keep your dog out of the garage while you work on the car.
- On walks, teach your dog not to pick things up: a reliable “leave it” protects against anything on the ground. If you find a suspicious bait in a public place, do not touch it with bare hands and report it to the local authority; if your dog is poisoned, keep the bait for the vet.
- Other household dangers are covered in our table on chocolate by dog weight; our health advice is gathered in the care and grooming section and on the dog hub.
Frequently asked questions
Which poisonings are the most urgent in dogs?
Those that progress within hours, such as metaldehyde slug pellets or antifreeze, whose treatment must start before the kidneys are affected. But an anticoagulant rat poison, silent for days, is just as urgent to report: the vet is most effective before signs appear.
My dog ate rat poison but seems fine: should I wait?
No. Signs of anticoagulants appear several days later. Call your vet with the packaging: they will decide on treatment, a clotting test or monitoring.
How can I tell whether my dog drank antifreeze?
The first sign looks like drunkenness: staggering, vomiting, thirst. If you saw your dog near a puddle under a car or a spilled container, call immediately, even if it seems better afterwards.
Are “organic” slug pellets safe for dogs?
They are generally less toxic than metaldehyde, but not harmless in large amounts. Store them like the others and call if your dog eats some.
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This guide is part of Planète Pets’s Dogs universe. Our advice is general in nature: for any health concern, your veterinarian remains the only reference.
