Rodenticide Poisoning In Cats & Dogs — Why the Type Matters

Author: Dr. Jason Nicholas

Published: October 21, 2016

Updated: May 27, 2021

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rat and mouse rodenticide is poisonous to dogs and cats

Not all rat and mouse poisons kill the same way

Many cats and dogs are brought into veterinary hospitals in the fall and winter after having gotten into a rat/mouse poison (“rodenticides”). After all, this is a common time of year for rats and mice to try and seek shelter in people’s homes and businesses, so it’s a common time of year for people to be putting out rat and mouse poisons.

While most people know that rat and mouse poisons are dangerous for cats and dogs, what many people don’t realize is that not all rodenticides work (kill) the same way. Because of this, it’s vitally important that you pay attention to what you and your neighbors are putting in and around your homes, and that the veterinary staff or the people at animal poison control are told (or better still, shown) which rodenticide your pet got into if exposure happens.

Along with the TYPE of poison (active ingredient, or at least the brand name), the amount of poison ingested, your pet’s weight, and how recently they got into the poison are all crucial pieces of information for poison control or the veterinary team caring for your pet to know. Without this information, determining the best treatment course of action can be more difficult –– which can mean otherwise avoidable tests or treatments (and therefore costs), as well as a greater chance of severe effects, or even death, for your pet.

Rodenticide classes and how they kill rats and mice (and cats and dogs)

Brodifacoum: Causes bleeding

Bromadiolone: Causes bleeding

Chlorphacinone: Causes bleeding

Difethialone: Causes bleeding

Diphacinone: Causes bleeding

Warfarin: Causes bleeding

Bromethalin: Prevents brain cells from making energy

Cholecalciferol: Interferes with calcium balance in the body

Strychnine: Causes severe muscle tremors and spasms

Zinc Phosphide: Prevents body cells from making energy

If your pet is poisoned by rodenticide bring the packaging to your vet

And if the packaging isn’t available, try to (safely) bring some of the poison along with you for the veterinary team to see — they may just be able to tell which one it is by its appearance. Here's a great resource with a list of the different types/classes of rodenticides, including what they do and how they differ.

Note that Bromethalin is a particularly dangerous type of rodenticide! It doesn't take much to cause problems and, unlike the anticoagulant (cause bleeding) rodenticides, there isn’t an antidote (medicine or remedy)! Treatment for Bromethalin poisoning is mostly supportive in nature, and once neurologic signs are present the prognosis is grave. Be extremely careful with this one, and should your pet ever get into it — 100% do not hesitate to contact animal poison control and seek immediate veterinary attention.

Speaking of particularly dangerous types of rodenticides... there is a compound, called Aldicarb, that is an extremely potent and deadly poison! The potency and fast kill are even touted in the name of an illegal, yet sadly still popping up, rodenticide called Tres Pasitos... which means "three little steps." According to the National Pesticide Information Center, Tres Pasitos usually finds its way into areas, typically large cities, due to illegal importation from the Dominican Republic, Mexico, and other Latin American countries. Nasty, nasty stuff! (We saw a case of Tres Pasitos toxicity in a dog when I was on my internship at The Animal Medical Center in New York City — very sad!)

Rat mouse poison in a bag

Rodenticide is so tempting for rodents (and pets) that they'll even eat through the packaging to get at it. Carefully store your unused rodenticide bait.

Pet-safer rodent control options

  • Electric Traps: Rather than bringing poison into your home, use a rodent trap that uses bait to lure the rodent in and then electrocutes them. The nice thing about these traps is that your pet can’t get inside (unless they are very small) and you won’t have to keep poison or bags of poison refills in your home.

  • Bait Stations: Some traps are designed so rodents can get in and eat the poison, but not a cat or dog. These are safer than unprotected poison, but not completely safe. There’s always the chance of a poisoned rodent leaving the trap and then being eaten by your cat or dog (this is called "relay toxicosis" or "secondary toxicosis"). And you still have to be careful to safely store the poison refills.

  • Catch-and-Release: There are traps that can help you remove rodents from your home without poisons or mechanisms (e.g., snap) that could also sicken, kill, or otherwise harm your cats and dogs. There are a number of catch-and-release traps that capture a mouse or rat without killing them, giving you the option to release the trapped rodent somewhere away from your home. (There are also glue traps that don't use poison to kill the rodent, but that doesn't mean they're "no kill." You still have to kill the live rodent on the trap or let them starve to death. And there's the added risk that your pet will get a glue trap stuck on themselves.)

How to prevent an accidental poisoning

Fortunately, even though not all rodenticides are the same, the simple steps you can take to protect your pets from rodenticides — regardless of their type and "method of kill" — are pretty much the same:rat poison while walking a dog

  • Keep dogs under leash control and don’t let them scavenge on walks — especially around parks, schools, and outside of restaurants.

  • Keep cats indoors.

  • If you use or store rodenticides in your home, be aware of what types you (or your landlord) are using and do so with a strict eye to the label instructions. And always, always, always keep them well and truly out of reach of your pets. This applies both to the pieces of poison laid out (or placed in a "bait station"), as well as the rest of what’s left in the box or bag!

  • Work only with exterminators who use pet-safer methods of rodent control.

  • Ask your neighbors not to leave any rat or mouse poisons in their yard, or to let you know in advance if they plan to.

  • Inquire about and double-check in and around any hotels/motels or rental apartments or homes you stay in with your pets while traveling.

  • Inquire about the presence of rodenticides within and around a home or apartment building prior to moving into a new house/apartment. Consider making removal of any rodenticides being used a condition of the purchase or rental agreement — your pet being poisoned by a rodenticide that you didn’t even know was there is a very unwelcome housewarming gift!

About the author

Profile picture for Dr. Jason Nicholas

Dr. Jason Nicholas

Dr. Nicholas graduated with honors from The Royal Veterinary College in London, England and completed his Internship at the Animal Medical Center in New York City. He currently lives in the Pacific Northwest.

Dr. Nicholas spent many years as an emergency and general practice veterinarian obsessed with keeping pets safe and healthy. He is the author of Preventive Vet’s 101 Essential Tips book series.

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