Rat poison can kill a cat, and the danger depends on what type of poison was eaten, how much, and how quickly the cat gets veterinary care. Most rat poisons fall into a few categories, each attacking the body in a different way. Some stop blood from clotting, some cause brain swelling, and others trigger kidney failure. In a retrospective study of 35 cats confirmed or suspected to have ingested rodenticides, the survival rate was 88.6%, but that number reflects cats that received veterinary treatment. Without intervention, the odds drop sharply.
Types of Rat Poison and What They Do
Not all rat poisons work the same way, and the type your cat ingested determines the symptoms, the timeline, and the treatment. There are four main categories you’re likely to encounter.
Anticoagulants are the most common. These poisons block the body’s ability to recycle vitamin K, which is essential for producing the clotting factors that stop bleeding. Without those clotting factors, a cat can bleed internally from even minor bumps or normal activity. The newer “second-generation” versions, like brodifacoum, are far more potent than older formulations. Brodifacoum alone accounts for over half of anticoagulant rodenticide exposures found in cat tissue samples.
Cholecalciferol (vitamin D3) poisons flood the body with calcium and phosphorus, overwhelming the kidneys. Acute kidney failure typically develops two to three days after ingestion. This type has a very narrow margin of safety, meaning even a small amount can cause severe illness or death. If kidney damage becomes chronic, there can be long-term consequences even for cats that survive.
Bromethalin is a neurotoxin that causes the brain to swell. Cats that ingest a lethal dose may show signs within 8 to 12 hours, though symptoms sometimes take several days to appear and can worsen over a week or longer. There is no antidote for bromethalin, which makes it particularly dangerous.
Alpha-chloralose is a sedative compound increasingly reported in cat poisonings. Cats are significantly more sensitive to it than dogs because their livers process it much more slowly, allowing the toxic effects to linger. It also makes cats especially vulnerable to hypothermia because of their high body surface area relative to their weight.
Symptoms to Watch For
The symptoms depend entirely on the type of poison, and they don’t always appear right away. This delay is one of the most dangerous aspects of rat poison exposure.
With anticoagulant poisons, signs can be delayed up to five days because the body has to use up its existing supply of clotting factors before bleeding becomes uncontrollable. When symptoms do appear, they can include lethargy, pale gums, difficulty breathing (from bleeding into the chest cavity), blood in urine or stool, nosebleeds, and unexplained bruising. A cat may seem perfectly fine for days before suddenly collapsing.
Bromethalin poisoning produces neurological symptoms: loss of coordination, seizures, vocalization, an inability to stand, depression, and eventually semicoma. Cats may adopt a rigid, abnormal posture as the brain swelling worsens. With strychnine, another neurotoxin found in some rodent products, signs can begin within two hours.
Cholecalciferol poisoning initially causes increased thirst, frequent urination, loss of appetite, and vomiting. These signs reflect the rising calcium levels that precede kidney failure. By the time kidney failure sets in around day two or three, the cat may become very lethargic and stop eating entirely.
Secondary Poisoning From Eating a Rodent
Cats don’t have to eat bait directly to be poisoned. A cat that catches and eats a mouse or rat that recently consumed poison can absorb enough toxin to become seriously ill. This is called secondary or relay poisoning, and it’s a real risk for outdoor cats and barn cats. Anticoagulant rodenticides are the most common cause of secondary poisoning because rodents carry residual poison in their tissues for days after eating bait. Even sublethal exposure to anticoagulants can weaken a cat’s immune system, damage the gut lining, and increase vulnerability to infections and parasites.
What to Do Immediately
If you suspect your cat has eaten rat poison, of any type, call your veterinarian or an emergency veterinary clinic right away. If you can’t reach a vet, the ASPCA Animal Poison Control Center (888-426-4435) and the Pet Poison Helpline (855-764-7661) are available 24/7.
Bring the packaging of the poison if you have it. The brand name, active ingredient, and concentration all help the vet determine how dangerous the exposure is and which treatment to use. Tell them approximately how much your cat weighs, when the exposure happened, and how much poison may have been consumed.
Do not try to make your cat vomit at home unless specifically instructed to by a veterinarian or poison control. Inducing vomiting is sometimes the right call, but in other cases it can make things worse. With neurotoxins like bromethalin, getting the cat to a hospital for intensive care is more important than attempting home decontamination.
How Veterinarians Treat Rat Poison Exposure
Treatment varies based on the type of poison. For anticoagulant rodenticides, the antidote is vitamin K1, which restores the body’s ability to produce clotting factors. Cats typically need to take vitamin K1 for several weeks because second-generation anticoagulants persist in the body for a long time. The vet will run blood clotting tests to monitor progress and determine when it’s safe to stop treatment. If bleeding has already started, a cat may need blood transfusions or plasma to stabilize.
For cholecalciferol poisoning, treatment focuses on aggressively lowering calcium levels and protecting the kidneys with intravenous fluids. One study found a remarkably good prognosis, with up to 100% survival, when decontamination and IV fluids were started within 48 hours and before acute kidney injury developed. Once the kidneys are damaged, the outlook worsens significantly.
Bromethalin has no specific antidote. Treatment is supportive: controlling seizures, reducing brain swelling, and managing symptoms as they arise. Early decontamination (removing the poison from the stomach before it’s fully absorbed) is critical and can make the difference between recovery and a fatal outcome.
Chances of Recovery
The odds of survival depend heavily on three factors: the type of poison, how much was consumed, and how quickly treatment begins. In a study of 166 poisoned cats, clinical signs appeared within a median of 3 hours after ingestion, and cats were brought to the clinic within a median of 6 hours. Among rodenticide cases specifically, 31 out of 35 cats survived.
Anticoagulant poisoning has a relatively good prognosis when caught in time because there’s a direct antidote. Cholecalciferol carries higher stakes because even small doses can be dangerous, and the window before kidney damage occurs is narrow. Bromethalin is the most unpredictable, since the lack of an antidote means treatment is limited to symptom management once the toxin has been absorbed.
Time is the single most important variable. A cat treated within hours of ingestion has a dramatically better chance than one brought in after symptoms have already advanced. If you have any reason to think your cat was exposed, even if the cat seems fine, getting to a vet before symptoms develop is far safer than waiting to see what happens.