Rat Poisoning in Cats

Heidi Kos-Barber, DVM
By Heidi Kos-Barber, DVM on Sep. 12, 2022
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In This Article


What Is Rat Poisoning in Cats?

If your cat has eaten any type of bait used to control rodent infestation, it is important that you seek veterinary attention immediately.

There are various types of rat baits sold in stores. Symptoms shown by cats who consume rat poison, and veterinary treatment plans, differ depending on the type of bait ingested.

Types of Rodenticides

Anticoagulant rodenticides function by interfering with vitamin K recycling in the body, which ultimately leads to a bleeding condition called coagulopathy. There are multiple types of compounds in this category, which are further divided into first- and second-generation anticoagulants.

Bromethalin is a neurological toxin that causes brain swelling, loss of normal brain function, and death.

Vitamin D3 (cholecalciferol) causes calcium to be held in the body and leads to high blood calcium and mineralization of tissues in the kidneys, lungs, heart, and blood vessels.

It is often difficult to figure out the amount of rat bait your cat has ingested. Therefore, consider ANY possible contact or ingestion of rodent bait by a cat toxic exposure, and seek veterinary attention immediately.

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Symptoms of Rat Poisoning in Cats

Anticoagulant rodenticide: Clinical signs may not occur until several days or even weeks after ingestion. Signs may include:

  • Lethargy

  • Pale gums

  • Bruising (on the skin, gums, whites of the eyes)

  • Black stool

  • Vomiting up blood

  • Difficulty breathing

  • Swelling of the joints

  • Blood in the urine

Bromethalin: Signs noted with toxicity depend on the amount your cat ingested. If a large amount, symptoms usually begin within a few hours. These may include muscle tremors, hyperthermia (high body temperature), seizures, or death.

If a small amount of bait is eaten, signs may not be noted for 1 to 4 days after ingestion. Usually, your cat will show signs of weakness and incoordination of the limbs, muscle tremors, paralysis, or cranial nerve abnormalities such as unequal pupil sizes or abnormal eye movements.

Vitamin D3: Clinical signs can be seen even at low exposure doses. A cat may become lethargic, start vomiting, drink more water than normal, have a higher volume of urine than normal, and have seizures. Death is possible.

Causes of Rat Poisoning in Cats

Rat poisoning occurs when cats come into contact with or consume rat bait or traps, or when a cat hunts and eats a rodent that has ingested the bait. Pet parents may see their cats consuming the bait or they may see evidence that a trap or bait has been tampered with, and suspect their cat got into it.

What Happens if a Cat Eats a Rat That Has Been Poisoned?

Relay toxicosis, where a cat eats a rodent that has consumed bait, can occur. Cats that eat multiple rodents over time could be at higher risk for toxicity because the toxin can build up in tissues. Anticoagulant and vitamin D3 poisons are stored in the liver of the rodent that ingests them. As a result, the more bait ingested by a rodent over time means a higher dose of toxin exposure for a feline hunter.

Alternatively, with bromethalin-containing baits, only a small amount needs to be ingested by a rodent to cause the rodent’s death. A larger amount needs to be ingested by a cat to see signs of toxicity. Therefore, a cat eating a rodent who consumed a bromethalin bait is not likely to die from it.

How Veterinarians Diagnose Rat Poisoning in Cats

Most often, veterinarians diagnose rodenticide poisoning based on a client history of seeing an exposure.

When arriving at the hospital, a veterinarian will ask what type of rat poison your cat was exposed to, how much, and how long ago. Bring the package of rat bait with you if possible. Since there are multiple types of rat poison and treatment varies depending on the type of bait ingested, it is important to come with as much information as possible.

Based on the type of bait your cat ingested or was exposed to, your veterinarian will most likely recommend baseline lab work, including a complete blood count and chemistries to check liver, kidneys, and electrolytes.

Anticoagulant rodenticide: If it has been a long enough time after exposure to this type of rodenticide, there may be evidence of bleeding (anemia) and prolonged coagulation times. If the cat is treated immediately after exposure, lab work may not be done initially; instead, it will be done at the end of the vitamin K treatment period.

Bromethalin: A specific diagnostic test is typically unhelpful. General lab work, including a complete blood count and chemistries may be performed.

Vitamin D3: A complete blood count and chemistries are performed. Bloodwork abnormalities include high blood calcium and phosphorus levels and elevated kidney values.

Unfortunately, there is no one superior “rat bait test.” Diagnosis of rat bait toxicity is made based on a combination of history, physical exam findings, and lab work.

Treatment of Rat Poisoning in Cats

Immediate treatment after ingestion or exposure to rat poison provides the best possible outcome, so you must take your cat to the veterinarian right away.

Giving hydrogen peroxide orally to induce vomiting is not advised, as the dose needed to cause vomiting can cause severe stomach swelling. Only a veterinarian should induce vomiting in a cat.

Decontamination is performed immediately at the veterinary clinic. Vomiting is induced using special medication. Once the veterinarian is satisfied with what the cat vomits up, medication will be given to cease further vomiting. Activated charcoal may be given to bind any possible toxin in the gastrointestinal tract of the cat so it can be eliminated from the body in the feces.

Anticoagulant rodenticide: If a cat gets to the vet immediately after exposure, he is likely not to be showing any signs of toxicity. Decontamination will be performed. The patient is usually treated on an outpatient basis with vitamin K and will have coagulation time and lab rechecked after treatment. The length of vitamin K treatment needed depends on the type of anticoagulant rodenticide ingested. Treatment for first-generation products, which are less toxic, is about 10 days, and for second-generation products it can be up to 4 weeks.

Once a cat is showing signs of bleeding, vitamin K alone will not be effective. The cat at this point it critically ill. Plasma transfusion to correct deficiencies in coagulation factors, a blood transfusion, and/or oxygen therapy may be needed. A cat in this state needs 24-hour care and may die despite the most intensive treatment.

Bromethalin: Treatment is supportive, as no antidote is available. Decontamination is performed, and multiple doses of activated charcoal may be given. Other medications include:

  • Muscle relaxers to treat tremors

  • Diuretics to reduce brain swelling

  • Anti-seizure medications to control seizures

  • Intravenous lipid emulsion to help eliminate the toxin from the body

Depending on the amount of exposure to the poison, treatment may vary.

Vitamin D3: Treatment is largely supportive, as there is no antidote. Intravenous fluids, intravenous lipid emulsion (early after exposure), and medications to help rid the body of excess calcium can be given. Bloodwork will be monitored over time to observe response to treatment. Prognosis is unclear once a cat is showing clinical signs, as kidneys and other tissues have already been damaged.

Recovery and Management of Rat Poisoning in Cats

In general, the sooner a cat is treated after toxin ingestion, the higher the likelihood is for a positive outcome. Depending on the toxin and the length of time that has passed since ingestion, the cat may be able to go home the same day with treatment or may be hospitalized for several days to a couple of weeks.

If toxicity is not addressed immediately, the damage caused by the toxin may not be reversible. The cat may develop lifelong health problems or even die.

Prevention of Rat Poisoning in Cats

The best way to decrease the risk of exposure to rat poison is to avoid having any poison around your home. Consider using pet-safe products to eliminate rodents. If you must use a product containing a toxin, block off pet access to bait stations.

Cats that are avid hunters are at a high risk for relay toxicosis by eating rats that have eaten toxins. Again, consider pet-safe alternatives or prevent access to rats by keeping your cat indoors and preventing access to a space where rats have been seen.


Backus, Jeffrey. Veterinary Information Network. A Toxic Challenge: Rodenticides.

Brooks, Wendy. Veterinary Information Network. Rat Poison (Bromethalin-Based) in Dogs and Cats.

Dekker, Mees. Veterinary Information Network. Bromethalin Toxicosis (Feline).

Gwaltney-Brant, Sharon. Veterinary Information Network. Anticoagulant Rodenticide Toxicosis (Feline).

Featured Image: iStock.com/Angela Kotsell


Heidi Kos-Barber, DVM


Heidi Kos-Barber, DVM


I am a small animal general practitioner in western Washington. The clinic I have worked at for the past 14 years sees a variety of...

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