Toxic Substances and your Pet


Here is a look at a few of some common household products that are toxic to your pet. This list is by no means complete, if you think your pet may have ingested something toxic, seek veterinary help.

Acetaminophen (Tylenol)

Acetaminophen is a common over the counter drug and most of us have it in our medicine cabinet. It is very important to keep this medication out of reach of your pets as it has a very narrow safety margin in cats and dogs, making it highly toxic to them. Cats and dogs can be poisoned by a small ingestion of the drug, however the clinical signs and problems associated with this toxicity differs in both cats and dogs.

Cats have an altered liver metabolism which makes them very susceptible to acetaminophen poisoning. Acetaminophen poisoning in cats affects their red blood cells and they develop methemoglobinemia. This means their red blood cells can not carry oxygen and this leads to lethargy, difficulty breathing, anemia and ultimately death if not treated for the toxicity.


Dogs usually don’t develop methemoglobinemia when faced with an acetaminophen toxicity unless a very large amount is ingested. Typically dogs will develop liver failure that can lead to jaundice, difficulty breathing, anemia and coma if not treated for the toxicity.

Thankfully there is an antidote for acetaminophen toxicity. Recovery is usually good with prompt administration of the antidote and veterinary supportive care (inducing vomiting, charcoal administration, IV fluids and blood work monitoring).


Human NSAIDs (Advil, Aleve, Naproxen, Voltaren, etc)

Human NSAIDs are also a very common medication in our medicine cabinet. There are veterinary specific NSAIDs that are safe to give to cats and dogs when given as prescribed by a veterinarian. NSAID toxicity can occur if your pet has ingested a human variety or has ingested a higher than prescribed dose of the veterinary type.

When an NSAID toxicity occurs it can result in gastric ulceration and kidney failure in dogs and cats. Symptoms of this toxicity can include vomiting and diarrhea (with or without blood), black stool, increased or inappropriate urination, seizures and coma. Recovery is usually good with veterinary supportive care (inducing vomiting, charcoal administration, gastroprotectant administration, IV fluids and urine/blood work monitoring).


Ethylene Glycol (Antifreeze)

Antifreeze containing ethylene glycol is extremely toxic to pets (there is “pet safe” antifreeze available that contains propylene glycol, which is slightly safer if ingested, but is still considered toxic). It only takes as little as a teaspoon of antifreeze to cause acute kidney failure and possibly death in your pet, making immediate veterinary treatment necessary.

Antifreeze poisoning occurs in 3 stages. Stage one looks similar to alcohol poisoning: in-coordination, vomiting and seizures can be seen. Stage two may look like your pet is recovered as primary symptoms usually resolve, however significant damage to the kidneys is occurring inside with minimal external symptoms. Stage three is when acute kidney failure occurs. Your pet will show symptoms of inappetence, lethargy, drooling, vomiting, seizures and coma leading to death.

Luckily there is an antidote for ethylene glycol toxicity. Recovery is usually good with prompt administration of the antidote (within 1-3 hours of ingestion) and aggressive IV fluid therapy.


Rodent Poison

There are four common active ingredients in rodent poisons: long-acting anticoagulants, cholecalciferol, bromethalin, and phosphides. Each has different active ingredients and different mechanisms of action. Treatment is different for each type of poison, therefore it is very important to make sure the product ingested in properly identified. If your pet has ingested rodent poison try to bring the original packaging to the clinic so appropriate treatment can be started. If your cat (or dog) is a hunter, be aware that hunting and eating mice that have ingested the poison can also lead to a toxicity in your pet.

Long-acting anticoagulants

These are the most common type of rodent poison. They prevent blood from clotting, resulting in internal bleeding. Symptoms from this type of poisoning results in lethargy, coughing, difficulty breathing and pale gums. Luckily there is an antidote for this type of rodent poison. By promptly inducing vomiting and starting a long term prescription of Vitamin K most pets make a full recovery. Blood testing to track clotting time is also done during recovery to ensure treatment is working.


This is the most potent rodent poison out there and it has a very narrow safety margin, meaning that even a small ingestion can quickly become fatal. When ingested the cholecalciferol causes extreme elevation in blood calcium levels, which ultimately leads to kidney failure and death. Symptoms include weakness, vomiting and increased urination and thirst. These symptoms may take over 24 hours to become apparent and unfortunately by then significant damage to the body is already done. There is also no antidote for this type of poison, making treatment difficult. Aggressive supportive care and frequent blood and urine monitoring is necessary for your pet to survive this type of toxicity.


Bromethalin type rodent poison causes swelling of the brain which results in neurological symptoms such as muscle tremors, seizures, and impaired movement when ingested. Like the cholecalciferol type of poison, bromethalin also has a very narrow safety margin. Since there is no antidote for this type of poison treatment revolves around decontaminating the patient. Inducing vomiting and IV fluids to flush out the system is the recommended treatment for this type of poison. An MRI or CT scan may be recommended after the patient is stabilized to determine the extent of swelling of the brain.


The phosphide type of rodent poisons work by releasing deadly phosphine gas, which is produced when the poison mixes with stomach acid. If your pet is suffering from this type of toxicity, there are two very important things to keep in mind. First, do not feed or give your pet anything to eat or drink, as this will increase stomach acid production and in turn increase phosphine gas production. Secondly, when transporting your pet to the clinic for treatment, open the windows in your vehicle. The gas produced that your pet is exhaling is toxic to people as well and having your pet in an un-ventilated vehicle can be harmful to you and can worsen your pet’s situation. Symptoms of this poisoning include drooling, stomach bloating, vomiting, abdominal pain, shock, collapse, seizures and death. Since there is also no antidote for this type of poison, inducing vomiting and IV fluids to flush out the system is the recommended treatment for this type of poison. Antacid administration may also be recommend to decrease stomach acid secretions, thereby decreasing gas production.

Helpful links:

ASPCA Animal Poison Control

Pet Poison Helpline