What Is Extremely Harmful To Cats?

Common Household Items

Many common household products can be extremely dangerous for cats. Cleaning products often contain harsh chemicals like bleach, ammonia, acids, and other toxic substances. According to What Household Items Are Dangerous to Cats? – Alley Cat Allies, household cleaners with these ingredients can cause severe burns or irritation to a cat’s eyes, skin, and digestive tract if ingested. Additionally, the strong fumes from cleaning products can be harmful if inhaled.

Human medications like acetaminophen/paracetamol, antidepressants, ADHD medications, and NSAIDs like ibuprofen can be toxic to cats, even in small doses. Cats’ bodies process medications differently than humans, so dosages safe for people can damage cats’ livers and red blood cells according to 15 Common Household Items That Can Kill Your Curious Cat – Atlantic Veterinary Seattle. Keep all medications secured safely out of pets’ reach.

Many common houseplants like lilies, azaleas, rhododendrons, sago palms, and more contain toxins that can cause kidney failure, tremors, seizures, and death in cats if ingested according to 8 Common Household Products Dangerous to Cats. Avoid keeping toxic plants in a cat’s environment and place safe, pet-friendly plants up high and out of reach.

Human Foods

Certain human foods are extremely dangerous for cats and can cause toxicity or poisoning.[1] Some of the most hazardous human foods for cats include:

Chocolate contains the stimulants caffeine and theobromine which are toxic to cats.[1] Even small amounts can cause vomiting, diarrhea, hyperactivity, abnormal heart rhythm, seizures, and in severe cases death.

Caffeine is also toxic to cats as they cannot metabolize it efficiently. It can cause restlessness, heart palpitations, tremors and even seizures.[2]

Alcohol has similar toxic effects in cats as in humans, causing vomiting, diarrhea, lack of coordination, difficulty breathing, tremors, abnormal blood acidity, coma and potentially even death.[1]

Grapes and raisins can cause sudden kidney failure in cats, even in small amounts. The exact cause is unknown but may be due to toxins contained in the fruit.[1]

Onions contain compounds that can damage red blood cells in cats, leading to anemia. Garlic contains similar compounds and is also hazardous.[2]

It’s important to keep human foods like these away from cats to avoid accidental poisoning. Cats should only eat a proper feline diet and approved cat treats.


Pesticides like insecticides, herbicides, and rodenticides can be extremely toxic to cats if ingested or absorbed through the skin. Common household pesticides contain chemicals like organophosphates, carbamates, pyrethroids, and glysophate which can poison cats.

Insecticides designed to kill roaches, ants, fleas, and other insects can be highly toxic to cats. Organophosphate and carbamate insecticides inhibit cholinesterase, an enzyme needed for proper nervous system function. Exposure can cause drooling, vomiting, diarrhea, seizures, respiratory failure, and even death in cats 1.

Herbicides used to kill weeds and unwanted plants can also pose a risk if cats walk through recently sprayed areas. Glyphosate herbicides like Roundup are considered mildly to moderately toxic to cats if ingested. Exposure may cause mouth ulcers, vomiting, and diarrhea.

Rodenticides designed to kill mice and rats are especially dangerous, as cats may eat poisoned rodents. Anticoagulant rodenticides prevent blood clotting and can cause severe bleeding disorders, anemia, and death in cats.

Keep all pesticides locked away or out of reach of cats. When using pesticides, follow label directions carefully and keep cats away from treated areas until dry. Signs of pesticide poisoning include drooling, vomiting, diarrhea, tremors, and seizures. Seek immediate veterinary treatment if poisoning is suspected.

Toxic Plants

Some of the most toxic plants for cats include lilies, sago palms, azaleas, and chrysanthemums. According to the ASPCA, all parts of the lily plant are extremely toxic to cats if ingested, including the pollen and even the water in a vase holding lilies (source). Lilies contain compounds that can cause kidney failure in cats within 3-7 days, and ingesting even a small amount can be fatal. The most dangerous types of lilies for cats are the Tiger, Day, Asiatic, Easter, Stargazer and some rubrum varieties.

Sago palms contain the toxin cycasin, which can cause severe liver damage or death in cats if ingested. Vomiting, jaundice, increased thirst, hemorrhagic gastroenteritis, bruising, coagulopathy, melena and liver failure are possible (source). All parts of the sago palm are toxic, including the seeds, leaves and roots.

Azaleas and rhododendrons contain grayanotoxins which affect sodium channels in cells and can cause vomiting, diarrhea, weakness, collapse, difficulty breathing, coma and even death in cats (source). Ingesting even a small amount of the leaves, flowers or nectar can be extremely dangerous.

Chrysanthemums contain pyrethrin toxins which can cause vomiting, diarrhea, hypersalivation, incoordination and tremors in cats. Ingesting stems, leaves and flowers can all be toxic. Long term exposure can cause liver and brain damage (source).

Prescription Medications

Many common human prescription medications can be extremely toxic to cats if ingested. Three major categories to be aware of are acetaminophen, ibuprofen, and antidepressants.

Acetaminophen, found in drugs like Tylenol, can cause severe liver damage in cats even in very small doses. Cats lack the necessary liver enzymes to metabolize acetaminophen safely. Source

Ibuprofen, the active ingredient in medications like Advil and Motrin, can cause stomach ulcers, kidney damage and even heart attacks in cats. It is the most common human medication that cats are exposed to. Source

Antidepressants like Effexor and Cymbalta can cause serotonin syndrome in cats, leading to agitation, elevated body temperature, heart rate and blood pressure. Even a small dose can be fatal. Always keep prescriptions safely out of reach of cats.

Veterinary Medications

Certain flea and tick treatments as well as heartworm preventatives can be extremely toxic to cats, especially if ingested orally.1 Flea and tick treatments containing pyrethrins or pyrethroids like permethrin can cause severe neurotoxicity in cats.2 Even small amounts can be fatal. Heartworm preventatives containing ivermectin can also be highly toxic to cats, causing neurological symptoms like disorientation, dilated pupils, and even coma or death.3 Veterinarians will prescribe flea, tick and heartworm products specifically formulated for cats to avoid toxicity. Pet owners should never use dog products on cats or give their cat medication without veterinary approval and oversight.

Automotive Chemicals

Common automotive chemicals like antifreeze, oil, and gasoline can be extremely toxic to cats if ingested. According to PetMD, petroleum products contain hydrocarbons that can cause severe pulmonary edema and hemorrhage when ingested or inhaled by cats.

Ethylene glycol in antifreeze has a sweet taste that attracts cats and dogs but is highly toxic. Even small amounts can cause kidney failure and death. Signs of antifreeze poisoning include vomiting, lethargy, increased thirst, ataxia, and seizures. Immediate veterinary treatment is required as antidotes need to be administered within hours to be effective.

Ingestion of used or fresh oil can cause aspiration pneumonia and chemical pneumonitis. Cats may walk through or ingest oil if it spills in the garage. Signs of oil poisoning include coughing, vomiting, diarrhea, and difficulty breathing. Washing the cat’s skin and fur to remove oil is recommended if exposure occurs.

Gasoline poisoning can occur from inhalation of fumes or ingestion during a spill. Gasoline contains benzene, toluene, xylene, and other toxic chemicals. According to Pet Health Network, signs of gasoline poisoning include difficulty breathing, vomiting, diarrhea, tremors, and lethargy. Immediate veterinary care is required.


Rodenticides are pesticides designed to kill rodents like mice and rats. They work by preventing the rodent’s blood from clotting normally, which leads to uncontrollable bleeding and eventual death.1 There are two main types of rodenticides that are extremely toxic to cats:

Anticoagulant Rodenticides

These are the most common type of rodenticides. They include chemicals like bromadiolone, brodifacoum, and warfarin. Anticoagulant rodenticides prevent blood clotting by blocking vitamin K metabolism.2 Cats are susceptible to anticoagulant poisoning because their livers cannot efficiently metabolize these chemicals. Just a small amount can lead to spontaneous internal or external bleeding within days.

Non-anticoagulant Rodenticides

These include chemicals like bromethalin, cholecalciferol, and zinc phosphide. They damage a cat’s central nervous system, liver, or heart muscle leading to seizures, heart failure, or sudden death.3 Non-anticoagulants act much faster than anticoagulants, with signs of poisoning showing up within hours of ingestion.

All types of rodenticides are extremely toxic to cats and require immediate veterinary treatment. Prevent access to rodenticides by keeping them in locked bait boxes that cats cannot get into. If ingestion is suspected, bring your cat to the vet right away.

Outdoor Hazards

Allowing cats to roam outdoors freely exposes them to many dangers that can threaten their health and safety. Some of the most hazardous perils for outdoor cats include cars, predators, and extreme weather.

Roads and vehicles pose a major risk. According to a 2020 study, uncontrolled outdoor access nearly triples the risk of cats being hit and killed by cars (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7070728/). Cats often crawl under vehicles for warmth without drivers realizing, and can get injured or killed when the car moves. Outdoor cats are also at risk of being hit by passing vehicles while crossing roads or wandering near traffic.

Outdoor cats face threats from predators like coyotes, foxes, bobcats, and birds of prey. These predators see unattended cats as easy targets for hunting. Even large dogs may attack and kill a cat they encounter roaming outside. Such attacks frequently result in severe injuries or death.

Extreme hot and cold weather creates hazards for outdoor cats as well. Cats can overheat in the summer without adequate shade and water. In the winter, frigid temperatures and storms put them at risk of frostbite, hypothermia, and freezing. Outdoor cats often seek shelter under car hoods or in uninsulated areas, where they are still vulnerable to the elements.

Signs of Poisoning

Some common signs that a cat has been poisoned include:

Vomiting – One of the first signs of poisoning in cats is vomiting. This may occur suddenly and repeatedly. Vomiting may be followed by drooling. According to Cornell University College of Veterinary Medicine, uncharacteristic bouts of vomiting are among the common clinical signs of poisoning in cats.

Seizures – Seizures or muscle twitching and tremors can be a sign of poisoning. Seizures may be mild or severe. Cats.org.uk states that twitching and fitting are signs of cat poisoning.

Difficulty breathing – Labored breathing, panting, or respiratory distress can indicate a cat has been exposed to a toxic substance. Cornell notes heavy breathing as a sign, while Cats.org.uk lists breathing difficulties.

Other signs like lethargy, diarrhea, shock or collapse, and skin inflammation may also occur with cat poisoning. Rapid identification of poisoning is critical, as some toxins can quickly become fatal if left untreated. Immediate veterinary care is recommended if poisoning is suspected.

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