If your cat ate a poisoned mouse, or a mouse you fear may have been poisoned, call now, before you finish reading. Call your veterinarian, the nearest 24-hour emergency animal hospital, the ASPCA Animal Poison Control Center at (888) 426-4435, or the Pet Poison Helpline at (855) 764-7661. Both US lines run 24 hours a day, and both charge a consultation fee. Do not make your cat vomit, and do not give any food, milk, oil, salt or home remedy unless a veterinarian or poison specialist tells you to, for this cat, right now.
This page is general information drawn from named veterinary sources. It is not written by a veterinarian, it does not diagnose your cat, and it does not replace that call. Its only job is to make the call faster and to help you answer the questions the specialist will ask.
Cat ate poisoned mouse: why you call even when it seems minor
A cat ate poisoned mouse situation is really two uncertainties stacked on top of each other. You usually do not know whether the mouse was poisoned at all, and even if it was, you do not know which poison. Those two unknowns are exactly why the safe move is a phone call rather than a judgment call at your kitchen table.
Veterinary sources describe poisoning that passes from a poisoned rodent to the animal that eats it as uncommon from a single mouse, but they do not describe it as impossible, and "uncommon" is not a result you can act on for your specific cat. The poison line exists to weigh the details you have, the product the neighbors used, your cat's size and health, the timing, against what a website cannot see. Let them make that assessment. It is what the fee buys.
Two different exposures hide behind the same worry
When people say a mouse "may have been poisoned," they are usually picturing one of two very different events, and the specialist will want to know which one you are describing.
- Secondary, or relay, exposure. Your cat ate a mouse that had itself eaten bait. The Merck Veterinary Manual, in its page on anticoagulant rodenticide poisoning in animals (read September 12, 2026), notes that nontarget species "may ingest recently poisoned rodent pests and develop relay or secondary poisoning." How much poison the carcass carries depends heavily on the rodent. Veterinary sources note that a rat eats far more bait in a day than a mouse does, so a poisoned rat generally carries a larger load than a poisoned mouse. That is a reason a single mouse is on the lower-risk end, not a reason to skip the call.
- Primary exposure. Your cat found and ate the bait itself, or licked at a bait station. This is the more dangerous of the two, because the cat gets the full product rather than a diluted trace inside a rodent.
If there is any chance your cat reached the actual bait, treat it as the more serious primary case and say so on the phone. And if you have no idea which happened, that uncertainty is itself worth reporting, not smoothing over.
Cats that hunt outdoors, live on farms or around stables or vineyards, or regularly eat what they catch sit at higher risk than an indoor cat who caught one mouse once. But higher and lower are the poison line's terms to apply, not yours.
The four rodenticides, and why the type changes everything
There is no single "rat poison." The Pet Poison Helpline page on mouse and rat poison (read September 12, 2026) describes four common active ingredients, and they behave so differently that the specialist's first question is often which one is involved. Critically, the antidote for one does not work on the others.
| Rodenticide type | How it harms a cat | Is there an antidote? | When signs may show |
|---|---|---|---|
| Long-acting anticoagulants (brodifacoum, bromadiolone, difethialone, diphacinone) | Stops blood from clotting, leading to internal bleeding | Yes: prescription vitamin K1, given only by a veterinarian | Delayed. Merck notes bleeding is typically seen 3 to 7 days after a toxic dose |
| Cholecalciferol (vitamin D3) | Raises calcium and phosphorus, causing acute kidney failure | No vitamin K1 antidote; a narrow margin of safety | Pet Poison Helpline notes kidney failure around 2 to 3 days after ingestion |
| Bromethalin | Swelling of the brain, causing neurological signs | No antidote | Pet Poison Helpline: possibly within about 2 hours at high doses, or delayed 3 to 4 days at lower ones; cats are more sensitive than dogs |
| Zinc or aluminum phosphides | Releases a toxic gas in the stomach | No antidote | Feeding after ingestion increases the gas produced; fumes from vomit can even affect people nearby |
Two points from that table matter more than the rest. First, vitamin K1 is a genuine, effective antidote, but only for the anticoagulant class, and only when a veterinarian prescribes and manages it. It does nothing for bromethalin or cholecalciferol. Second, the Pet Poison Helpline stresses that you cannot identify the active ingredient by the color or shape of the bait; the label, and specifically the active ingredient name and EPA registration number, is what tells the specialist which clock you are on.
Why "wait and see" is a bet against a clock you cannot see
The most common rodenticides do their damage quietly for days. With the anticoagulant type, Merck explains that a poisoned animal still has a supply of working clotting factors on board, so those have to run down before anything looks wrong. Merck puts the delay in the numbers a specialist watches at 2 to 5 days, with visible bleeding usually 3 to 7 days after a toxic dose. Cholecalciferol and bromethalin have their own delays, listed above.
This is the trap the whole page is built to help you avoid. A cat who looks completely normal tonight has not been cleared. She may simply be inside the window before signs appear, which is also the window in which treatment tends to work best. That is why every veterinary source says the same thing: act on the possible exposure, not on the presence of symptoms. Do not wait to see if she gets sick.
The mouse itself is a separate question
Even setting the poison aside, a whole mouse is not nothing. It can bring on a bout of vomiting or an upset stomach, and some cats react to a large, unfamiliar meal of prey. Do not use those signs to diagnose poisoning in either direction; report them, because they can also be early signs of several of the toxins above.
Owners sometimes worry about the bones in a swallowed mouse. Small raw prey bones are a different question from cooked bones and fat trimmings, which splinter in a way raw bone does not, but any straining, retching, or change in your cat's appetite or litter box still belongs on the call. While you have a poison line's number saved, it is worth knowing that cats are unusually sensitive to some everyday foods too: the Merck Veterinary Manual names cats as the most susceptible species to the Allium family of onion and garlic, which is one more reason a cat is not a small dog when it comes to what she eats.
What to have ready when you call
The call moves faster, and the advice is better, when you have gathered a few things first. Do this while someone else dials, or with the phone on speaker.
- The bait, its box or a photo of the label. The active ingredient name, the concentration and the EPA registration number are what pin down the poison type. If the bait belongs to a neighbor, ask them for the product name.
- The mouse, if you still have it, kept safely away from the cat and any other pet.
- The timeline. When it happened, or the last time you know your cat was fine.
- Your cat's details. Approximate age and weight, and any known health conditions.
- What you have seen since, including "nothing," and anything you may have already given her.
What not to do
Do not induce vomiting on your own. Whether a cat is made to vomit is a decision a veterinarian makes, often in the clinic, and for some substances it is dangerous. If your cat reached the bait very recently, a vet may choose to do this, but that is their call to make quickly and safely, not yours to attempt at home.
Do not feed her to "soak it up." For the phosphide type of bait, the Pet Poison Helpline notes that food in the stomach actually increases the toxic gas produced, so feeding after a suspected phosphide exposure is never recommended. When you do not know the poison, you do not know that feeding is safe.
Do not give any home antidote. Milk, oil, salt, bread and internet remedies are not treatments, and some make matters worse. Vitamin K supplements you might have at home are not the prescription-strength, veterinary-managed vitamin K1 that anticoagulant cases need, and self-treating can mask the very signs a vet is watching for.
Do not wait for symptoms, for all the reasons in the timing section above.
The honest limit of this page
No website can tell you whether your cat has been poisoned, or how badly. This page cannot see the bait, weigh the amount, judge your cat's health or read the clock the way a specialist can, and by site policy it will never give you a dose or a threshold to measure against. What it can do is show you why a single unknown mouse hides two separate uncertainties, why the type of poison changes everything, and why a normal-looking cat tonight is not a cleared cat. Then it can send you to the phone, which is where this always ends.
FAQ
My cat ate a poisoned mouse but seems totally fine. Do I still need to call?
Yes. The most common rodenticides act with a delay: Merck describes visible bleeding from the anticoagulant type typically 3 to 7 days after a toxic dose, and the Pet Poison Helpline describes kidney signs from cholecalciferol around 2 to 3 days after. A cat that looks fine now may be inside that window, which is also the window when treatment works best.
How likely is it that one poisoned mouse will actually hurt my cat?
Veterinary sources describe secondary poisoning from a single mouse as uncommon, partly because a mouse carries far less bait than a rat does. But uncommon is not zero, and only a vet or poison specialist can weigh your cat's size, health, the product involved and the timing. Let them make that call.
Should I make my cat throw up at home?
No, not on your own. For some rodenticides inducing vomiting is dangerous, and for the phosphide type even feeding is discouraged because it increases toxic gas. Whether to induce vomiting is a decision a veterinarian makes, usually in the clinic and quickly.
The neighbors used the bait. How do I find out which poison it was?
Ask them for the product box or a photo of the label, and give the poison line the active ingredient name and EPA registration number. The Pet Poison Helpline notes you cannot identify the ingredient by the bait's color or shape, and knowing the type tells the specialist whether an antidote such as vitamin K1 even applies.
Is there an antidote for rat poison?
There is one for the anticoagulant class, prescription vitamin K1, but it must be prescribed and managed by a veterinarian, and it does not work on bromethalin or cholecalciferol baits. That is exactly why identifying the poison type matters so much.
Sources read at the source on September 12, 2026 and named above: Merck Veterinary Manual, "Anticoagulant Rodenticide Poisoning in Animals" (Toxicology); Pet Poison Helpline, "Mouse and Rat Poison." Emergency contacts: ASPCA Animal Poison Control Center (888) 426-4435 and Pet Poison Helpline (855) 764-7661, both 24-hour US lines that charge a consultation fee.
This page is general information, not veterinary advice, and it does not diagnose or treat. If your cat may have eaten a poisoned mouse or any rodent bait, the call comes first.