12 min read

Top 10 Most Common Poisonous Substances for Cats


By Leslie Ingraham

Published: 03/08/2022, edited: 04/29/2022

Reviewed by a licensed veterinary professional: Dr. Linda Simon, MVB MRCVS

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Accidental poisoning in cats is more common than most of us might expect. This is because of their fastidious grooming, curiosity, relatively small body size, and an increased sensitivity to drugs and chemicals. But eating or drinking a toxic substance isn’t the only way a feline can be poisoned. 

Grooming themselves when their fur has a toxic substance on it, or eating a poisoned animal or bird can result in illness or death. Some human foods are extremely toxic to cats, as well as some medications, plants, and household solutions. The ASPCA Animal Poison Control Center (APCC) tracks calls from distraught pet parents and estimates it receives about 400,000 annual inquiries about poisoned pets.

National Pet Poison Prevention Week is March 20-26, and is the purrfect time to get the word out about how to prevent poisonous substances from making your cat ill. Let’s take a look at the APCC’s Official Top 10 Pet Toxins, along with their symptoms and treatment, so pet parents will be prepared to recognize feline poisoning and respond to it quickly. 

ibuprofen bottle with pills - most common poisonous substances for cats


Many over-the-counter (OTC) human medications can cause problems for cats, and OTC drugs are responsible for about 17% of the reported poisoning cases. Ointments and creams meant for soothing sore joints and supplements like human vitamins can also result in poisoning, but one of the most common OTC culprits is non-steroidal anti-inflammatory drugs (NSAIDs) like ibuprofen that reduce inflammation and its associated pain. About 300 annual calls to the Pet Poison Helpline concern the accidental feline ingestion of ibuprofen or another anti-inflammatory drugs made for humans. It is not uncommon for pet parents to give these medicine to their pets, thinking they are doing good and not understanding the devastating consequences.

Symptoms of ibuprofen poisoning in cats

While your veterinarian may prescribe safe feline NSAIDs like Metacam, carprofen, and tolfenamic acid, it’s important to remember not to give your fluffy friend human NSAIDS of any kind unless your vet has prescribed them. 

Several organ systems may be affected by ibuprofen poisoning in cats. Symptoms vary by dose and the product administered. Ibuprofen can be a single ingredient in a medication, or combined with other substances like acetaminophen that are also toxic to cats. 

Symptoms of ibuprofen poisoning in cats include:

Treatment for ibuprofen poisoning in cats

Treatment of ibuprofen toxicity will depend on the amount ingested, the length of time between ingestion and treatment, and the overall health of the cat. It’s important to consult a vet to determine the severity of the toxicosis (poisoning) as soon as possible after the cat has ingested the ibuprofen. Treatment focuses on ridding the system of the toxin, sometimes by inducing vomiting. Following that, activated charcoal may be given to prevent further toxin absorption from the GI tract. 

Hospital care may be necessary during the acute phase of poisoning. Intravenous fluids will be administered, along with medications to protect against liver failure, continued gastrointestinal problems, seizures, and kidney failure. Muscle relaxants can help alleviate discomfort in the cat with tremors or seizures. Your veterinarian will want to monitor your cat’s progress and watch for complications that may arise. Metabolic blood panels may be performed to keep an eye on the kidneys and liver, and blood cell counts will indicate whether anemia has resulted from internal blood loss.

Average cost of treating ibuprofen poisoning: $500

Pile of antidepressant capsules spilling out of open bottle


Antidepressants are made with ingredients that seem to smell and taste good to cats. Venlafaxine (Effexor) is especially appealing to them, along with several other SSRI (serotonin reuptake inhibitor) antidepressant medications including fluoxetine (Prozac), sertraline (Zoloft), and paroxetine (Paxil).  Tricyclic antidepressants such as imipramine (Tofranil) and nortriptyline (Pamelor) can cause similar toxicity symptoms as SSRIs. Overdoses can occur after a cat accidentally ingests human antidepressants, or takes a feline dose that’s too much for them. 

Symptoms of antidepressant poisoning in cats

Even a single tablet of a low-dose antidepressant can have serious toxic effects on a cat. Cats that normally resist taking pills may willingly eat an antidepressant that is left out where they can get to it. In cases of antidepressant poisoning, a cat’s symptoms will include:

Treatment for antidepressant poisoning in cats

Prompt treatment is critical. Only the vet will be able to definitively diagnose the problem and initiate life-saving treatment. A physical exam will be followed by questions for the pet parent about how many pills were ingested and when they were eaten. 

Treatment includes inducing vomiting to rid the stomach of the medication, and IV fluids to help dilute the amount in the cat’s system. Fluids may replace those lost from vomiting, thus preventing dehydration. A period of monitoring, along with supportive care for symptom relief, may be necessary. Sedation can help until the medication has been flushed from the cat’s body. This may take one to three days.

Average cost of treating antidepressant poisoning in cats: $2,500

Brown dog laying down to receive topical flea and tick medication

Canine flea and tick medications

Any animal could possibly overdose on veterinary medications, but the most common ones known to be poisonous to cats are parasitics such as canine flea and tick prevention medications.

Many pet owners think that cats are the same as small dogs from a metabolic standpoint, but in reality, just giving a smaller dose of topical or edible canine flea and tick medication to a cat can be fatal. These medicines contain pyrethroids such as permethrin, which are highly toxic to cats. 

Whether the flea and tick preventative is given directly to the cat, or is rubbed or licked off during contact with a medicated dog, the results can be life-threatening. Other parasitics like the ivermectin in Heartgard are safe for cats, but can be toxic if a cat accidentally overdoses on the tempting beef-flavored chewy medication in dosages for dogs, as can happen with any tasty chewable. All veterinary-prescribed medications should be stored out of reach of pets. 

Symptoms of canine flea and tick medication poisoning in cats

Ingestion of permethrin or related pyrethroids will cause gastrointestinal and neurological symptoms that include:

  • Severely excessive drooling
  • Nausea
  • Vomiting
  • Unsteadiness
  • Labored breathing
  • Eye symptoms (tearing, dilated pupils)
  • Disorientation
  • Loss of appetite
  • Muscle tremors
  • Seizures
  • Collapse

Treatment of canine flea and tick medication poisoning in cats

The focus of treatment is to stabilize the cat, including initiating IV therapy. Medication may be administered through the IV route; including diazepam or phenobarbital, which are sedatives that combat seizures. 

Complications from canine flea and tick medication poisoning can include liver failure, kidney failure, encephalitis, hypoglycemia, and anemia. Symptoms will be treated with medication and fluids until the toxins are cleared from the cat's body.

Average cost of treating parasitic poisoning in cats: $600

calico cat sniffing an onion and garlic bulb


Onions, and other members of the Allium plant family such as leeks, garlic, and chives, can cause toxicity if a cat eats them in excessive amounts or over prolonged periods of time. These plants can cause red blood cell destruction, leading to anemia. 

Symptoms of onion poisoning in cats

If a cat ingests food from the Allium family, anemia may result from a reduction in the number of red cells circulating in the blood. Some of the symptoms of onion poisoning in a cat are the direct result of cell destruction. 

  • Lethargy
  • Pale mucous membranes
  • Abdominal pain
  • Vomiting
  • Diarrhea
  • Difficulty breathing (dyspnea)
  • Tachycardia
  • Blood in the urine
  • Weakness
  • Jaundice
  • Collapse

Treatment of onion poisoning in cats

The most common treatment for onion poisoning in cats is hospitalization to provide supportive care and provide time for the toxin to stop destroying red cells. Supportive measures include intravenous fluids to flush toxins and dead red cells out of the body, and rest while the bone marrow produces new red blood cells. If enough red cells have been lost, a blood transfusion may be necessary. Antiemetic and antidiarrheal medication may be necessary to calm the GI tract down, as well.

If signs of liver failure or kidney failure are present, medications to help restore the organs to a more healthful state may be prescribed.

Average cost of treating onion poisoning in cats: $2,000

chocolate pieces and shavings


Most dog owners are aware of the dangers of chocolate for their pups, but cat parents must watch for accidental chocolate poisoning as well. Besides containing harmful toxins such as theobromine, chocolate typically has high levels of fats and sugars, both of which are unhealthy for cats, leading to abdominal symptoms. Theobromine produces neurological and cardiovascular symptoms. Too much chocolate and sugar can also cause serious, sometimes life-threatening pancreatitis.

Symptoms of chocolate poisoning in cats include:

  • Hyperactivity
  • Vomiting
  • Diarrhea
  • Dehydration
  • Elevated heart rate
  • Cardiac arrhythmias
  • Hypertension
  • Muscle tremors
  • Panting
  • Hyperthermia
  • Frequent urination
  • Lethargy
  • Seizures 
  • Collapse

Treatment of chocolate poisoning in cats

It’s critical to take your cat to the vet as soon as you think they’ve ingested chocolate in any form. To remove chocolate from the cat’s stomach, the veterinarian will induce vomiting through a feeding tube. Activated charcoal may be administered immediately to absorb the remaining toxins from the GI tract.

Supportive care may include fluids to combat dehydration and dilute the toxins. Medications may be administered to alleviate cardiac symptoms, and antiemetic and antidiarrheal drugs may be included as well. If seizures are severe and unrelenting, anticonvulsants may be given.

Average cost of treating chocolate poisoning in cats: $500

black cat exploring an orange and red lily


While we love to invite the outside in with houseplants, some can be downright deadly to your feline pal. Sago palm, tulips, and chrysanthemums are a few troublesome plants to steer clear of, but lilies are considered to be highly poisonous.

Leaves and blossoms from plants of the lily family can cause toxicosis in cats, even if eaten in very small amounts. Some cats may even become ill after licking the water in the bottom of the plant pot or from the vase. The most common culprits are Easter lilies, Stargazer lilies, and Tiger lilies. Milder symptoms may be caused by Calla lilies and Peace lilies, although they’re not true lilies. 

Symptoms of lily poisoning in cats

Signs of lily poisoning may appear within six to 12 hours after ingestion. Immediate care is crucial to preventing severe illness like irreversible kidney failure. Milder symptoms are usually associated with calla and peace lilies. Signs of lily poisoning in cats include:

  • Mouth and tongue irritation
  • Gum ulceration
  • Irritation of the throat and esophagus
  • Loss of appetite 
  • Lethargy
  • Vomiting
  • Excessive thirst
  • Frequent urination
  • Disorientation
  • Inability to walk
  • Seizures

Treatment of lily poisoning in cats

The initial response to a cat with ingested lily toxicity will be to stabilize them with medication and IV fluids. Replacement of fluids to treat kidney failure, and medication to control disorientation and possible seizures may be prescribed. 

The second line of treatment is to eliminate the toxins that may remain in the cat’s stomach by inducing vomiting. The cat will often receive activated charcoal to soak up any remaining toxins, along with medication to control nausea and vomiting. Follow-up tests will determine the treatments’ effectiveness and prevent further complications. 

Average cost of treating lily poisoning in cats: $3,000

house cleaners sitting on wood floor

Household substances

Household cleaners and other substances can be irritating to a cat’s skin and lead to poisoning. A feline can lick these chemicals from a container or the floor, or get them on their fur and ingest them during grooming. These dangerous substances include paint, paint thinners, and other solutions or pastes. Coolant, motor oil, antifreeze, and gasoline under the car on the garage floor can poison felines as well. 

When using household chemicals like bathroom and carpet cleaners, be sure your cat doesn't have access to the area until the solutions are completely dry to prevent poisoning. Even if the cat only gets the chemical on their feet, they can lick it off.

Symptoms of a household substance poisoning in cats

Cleaners and other chemicals can cause symptoms ranging from mild mouth irritation to damage to the respiratory and other organs. Some of the symptoms pointing to chemical poisoning include:

  • Profuse drooling
  • Difficulty breathing
  • Wheezing
  • Vomiting
  • Mouth ulcers
  • Gastrointestinal ulcers causing pain and bleeding
  • Hyper urination
  • Excessive water consumption
  • Decrease or loss of appetite

Treatment of household substances poisoning in cats

The first step in treatment is to get the cat to the veterinary clinic immediately if evidence or suspicion of inhalation or ingestion is present. Speed is so important that it’s recommended that pet parents bundle the cat into the car right away and call the vet or emergency clinic on the way. 

If the cat has evidence of a chemical on its coat or feet, wrap them in a towel to prevent them from ingesting more of it. A towel will also protect against injury to humans or the cat.

The clinic staff will bathe the cat if the poison is on the skin or fur, but in this case won’t induce vomiting because the chemicals can cause throat or mouth irritation. IV fluids will be initiated, and antiemetics may be given. Activated charcoal may be administered through a stomach tube. Respiratory symptoms will be treated with oxygen or an endotracheal tube in extreme scenarios.

Average cost of treating household solution poisoning: $2,000

man spraying bush with insecticide


Ingestion of preparations used to kill insects and other pests in the house or garden can make a cat very ill. In products ranging from bug sprays to ant traps to slug bait, two substances that are especially poisonous are carbamates and organophosphates. Federal and state regulations have made insecticide use safer for cats and other pets, but Pet Poison Helpline inquiries about pesticides number in the hundreds each year.

Symptoms of insecticide poisoning in cats occur in the neurological, respiratory, renal, and gastrointestinal systems. They can be severe enough to overwhelm the systems to the extent that they fail completely. These symptoms can include the following:

  • Hypersalivation
  • Diarrhea
  • Abdominal cramping
  • Vomiting
  • Sweating 
  • Bluish coloring of mucous membranes (cyanosis)
  • Difficulty breathing
  • Tremors 
  • Severe muscle spasms
  • Seizures 

Treatment of insecticide poisoning in cats

Immediate attention from a veterinarian is critical in treating cats with insecticide poisoning. If possible, make ingredient information available to the vet and report on how long ago and how much the cat ingested. Some treatment modes will depend on this data.

The aim of treatment is to rid the cat of the toxin and treat symptoms until the feline is toxin-free. Methods include inducing vomiting or removing stomach contents through a gastric tube, followed by the administration of activated charcoal to absorb any remaining chemicals from the GI tract. IV therapy may be started to counter dehydration and flush poisons out via the urinary tract system.

Antidotes like atropine treat nervous system symptoms from organophosphates. Identification of the chemical is important to initiating this lifesaving treatment. Supportive treatments like antiemetics and antidiarrheal medications, anti-seizure meds, and respiratory support with oxygen will be applied as needed. If the cat is feverish, medications to lower temperature may be administered, along with measures such as applying ice to pulse points. 

Average cost of treating insecticide poisoning in cats: $600.

rat trap with rat poison in a corner of house

Rat Poison

Rodenticides are used to eliminate rats and other rodents in and around the home. They can cause toxic effects requiring veterinary care. The appeal of rodenticide for rodents can also attract a cat, with disastrous results. 

Rodenticides often contain cholecalciferol, the same feline poison in Vitamin D3 that causes toxicity. Other rat poison traps may contain brodifacoum or bromethalin as well, both of which are dangerous to cats. Because symptoms of rat poisoning toxicity remain hidden for one to three days, there is often severe kidney damage already in place before the toxicity is discovered.

Cats can also consume rodenticides by eating animals that have it in their system. It’s important to avoid using these toxic substances in or near a home with cats.

Symptoms of rodenticide poisoning in cats

Symptoms in cats that have ingested a rodenticide will vary with the type and amount eaten. Some rodenticides contain chemicals like warfarin derivatives that affect the animal’s blood clotting function. Others affect the neurological system, the GI tract, or the renal system. Each of these conditions will come with their own set of symptoms, such as:

  • Nosebleeds or other abnormal bleeding
  • Prolonged clotting time
  • Bruising 
  • Blood in the urine
  • Bloody stools
  • Breathing difficulties
  • Panting
  • Lack of appetite
  • Abdominal bloating
  • Vomiting, sometimes with traces of blood
  • Drooling
  • Pale mucous membranes
  • Unsteadiness
  • Lethargy
  • Irrational or violent behavior
  • Excessive thirst
  • Seizures
  • Metabolic tests that show kidney failure

Treatment of rodenticide poisoning in cats

Treatment of rodenticide poisoning is typically aimed at relieving or correcting symptoms. It is also focused on ridding the cat’s GI system of toxins by inducing vomiting and administering activated charcoal. To treat problems with blood clotting, vitamin K may be given, along with IV fluids or whole blood to replace blood and fluid loss. IV fluids also treat dehydration. 

The cat may need respiratory support with an endotracheal tube or oxygen mask, along with placement in a room with little light or noise to prevent or stop seizures. Antiseizure medications may be administered intravenously. Hospitalization for rest and observation is almost always required.

Average cost of treating rodenticide poisoning in cats: $3,000 

human hand dropping fertilizer pellets into soil


There are many types of fertilizers on the market, most of which contain potassium, nitrogen, and phosphate. Most fertilizer may cause some minor GI problems, but won’t be severely poisonous to cats. However, many garden and lawn fertilizers contain added ingredients that may be harmful.

Harmful ingredients include bone meal, insecticides, herbicides, and iron. The effects these ingredients can have range from mild symptoms to pancreatitis and neurological signs like tremors and seizures.

Symptoms of fertilizer poisoning in cats

As mentioned, symptoms of fertilizer poisoning in cats can be widely variable depending on the fertilizer’s makeup and the amount ingested. Some of the signs to watch out for include:

  • Nausea
  • Vomiting
  • Drooling
  • Breathing difficulties
  • Abdominal pain
  • Bloating
  • Seizures
  • Pancreatitis

Treatment of fertilizer poisoning in cats

Treatment for fertilizer poisoning will depend on what’s in it and how much the cat has in their system. Cats don’t often ingest a lot of fertilizer as dogs might, but even licking off what they pick up by walking, playing, or rolling on a newly fertilized lawn can be significant. Cats are small, and their livers can be inefficient at ridding their body of toxins.

Treatment is aimed at eliminating the fertilizer from the cat’s stomach with vomiting, and then absorbing the remaining harmful chemicals by administering activated charcoal. Cats will often present with acute vomiting and the vet may skip inducing vomiting in this case. 

Medical treatment consists of fluid support, medications to alleviate symptoms such as pain and bloating, and reducing the likelihood of seizures. Observation in the hospital for a day or two is common practice. Complications such as kidney or liver failure, pancreatitis, or respiratory problems will need further treatment if they arise.

Average cost of treating fertilizer poisoning in cats: $1,000

The most effective way to help protect your feline buddies from poisons is to identify potentially harmful products, foods, and medications, and to secure them in a way that will prevent cats from accessing them. Bins with locking lids, cabinets that a cat can’t easily open, or storage behind a closed door are all ways to keep them away from your cat.

Got more questions about cat poisoning? Chat with a veterinary professional today to get the lowdown on toxicity in cats.
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