Rat Poison poisoning in dogs and cats
Toxic agent: Four different active ingredients with nothing in common · Reviewed 2026-08-18
Phone a vet now, before reading on. Have ready: your pet's weight, roughly how much was eaten and when, and the packaging if there is any. ASPCA Animal Poison Control (+1 888 426 4435), Pet Poison Helpline, or Animal PoisonLine in the UK.
There is no such thing as generic rat poison. Four unrelated chemistries are sold in similar-looking blue and green blocks, they poison in completely different ways, and only one of them has an antidote. Find the packet.
What it actually does
Anticoagulants block vitamin K recycling, so clotting factors run out and the animal bleeds internally days later. Bromethalin uncouples oxidative phosphorylation in the brain and causes cerebral oedema. Cholecalciferol floods the body with vitamin D, driving calcium so high it calcifies the kidneys. Zinc phosphide releases phosphine gas in the stomach. Same shelf, four different emergencies.
How much matters
What to tell the vet, by active ingredient:
| Anticoagulant (brodifacoum, bromadiolone, difenacoum) | bleeding at 3–5 days; vitamin K1 is an effective antidote, given for weeks |
|---|---|
| Bromethalin | neurological signs in 2–24 hours; no antidote, very narrow margin |
| Cholecalciferol | kidney failure over 1–3 days; no true antidote, hardest to treat |
| Zinc phosphide | vomiting and phosphine gas within hours; ventilate the room, the vomit is hazardous to humans |
The single most useful thing you can do is bring the packaging or photograph the active ingredient panel. Colour and pellet shape do not identify the chemistry, and the treatment differs completely.
What you will see, and when
Onset: 2 hours to 5 days depending entirely on which one. Typical course: Days for bromethalin and zinc phosphide; up to a month of vitamin K for anticoagulants.
- Anticoagulantnothing for 3–5 days, then pale gums, coughing, bruising, blood in urine, sudden collapse
- Bromethalintremors, hind limb weakness, seizures, coma over hours to a day
- Cholecalciferolvomiting, thirst and excessive urination, then kidney failure over 1–3 days
- Zinc phosphiderapid vomiting, bloating, difficulty breathing, garlic or fish odour to the vomit
What the vet will do
Decontamination, then it splits: vitamin K1 with clotting time monitoring for anticoagulants; intravenous lipid emulsion, mannitol and repeated charcoal for bromethalin; fluids, drugs to lower calcium and days of monitoring for cholecalciferol; supportive care and ventilation for zinc phosphide.
Outlook
Anticoagulants: good, if the full course of vitamin K is completed. Bromethalin and cholecalciferol: guarded to poor.
Dogs and cats are not the same here
Both. Cats are also at risk of relay toxicity from eating a poisoned rodent, particularly with anticoagulants.
Where it comes from in a normal house
- Bait blocks and pellets in sheds, garages and lofts
- Bait boxes placed by a pest controller, sometimes without the resident knowing the ingredient
- Poisoned rodents in the garden
- Neighbouring properties — a dog can eat bait it found next door
The thing people get wrong
“The vet gave vitamin K, so whatever it was is covered.”
Vitamin K is the antidote for one of the four families and does nothing for the other three. Identifying the active ingredient is not administrative box-ticking, it decides the entire treatment.
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Get PawLife on the App StoreFrequently asked questions
How much Rat Poison is dangerous?
The single most useful thing you can do is bring the packaging or photograph the active ingredient panel. Colour and pellet shape do not identify the chemistry, and the treatment differs completely.
How long after exposure to Rat Poison do symptoms start?
2 hours to 5 days depending entirely on which one. nothing for 3–5 days, then pale gums, coughing, bruising, blood in urine, sudden collapse. Days for bromethalin and zinc phosphide; up to a month of vitamin K for anticoagulants.
Is Rat Poison worse for cats or dogs?
Both. Cats are also at risk of relay toxicity from eating a poisoned rodent, particularly with anticoagulants.
Is it true that: The vet gave vitamin K, so whatever it was is covered.
Vitamin K is the antidote for one of the four families and does nothing for the other three. Identifying the active ingredient is not administrative box-ticking, it decides the entire treatment.
Related emergencies
Sources
This page is information, not veterinary advice. Toxic doses vary with body weight, age, breed and individual sensitivity, and the figures above exist to explain what a vet is assessing, never to decide that an amount is safe. If you are reading this because something has already been eaten, call a vet.