Educational Resources

Cat Toxins

Many common household plants, foods, human medications, and household products are toxic to pets. Cats can be exposed to these harmful substances through ingestion, grooming, inhalation, or skin absorption. This article discusses the most common toxins that can be life-threatening to cats and may require immediate medical attention.


Lilies—Lilies are EXTREMELY TOXIC to cats. Although the exact chemical that causes the toxicity has not been identified, it is known that ingestion of any part of the lily plant (flower, stem, leaf) can cause acute, often irreversible kidney failure within 24 hours. Lily intoxication is often fatal.

Many plants (Ivies, poinsettias) contain calcium oxalate crystals that can cause gastrointestinal upset and oral irritation. Please visit the ASPCA’s website for a list of toxic and non-toxic houseplants.


Onions/Garlic—Onions and to a lesser extent, garlic contain a compound (N-propyl disulfide) that causes the destruction of red blood cells (Heinz body anemia). Many cat foods contain very small amounts of garlic or onion powder for flavor—these amounts are considered to be safe.

Chocolate—Contains a compound (theobromine) that is similar to caffeine. Exposure can cause panting, hypersalivation, and tremors that can progress to heart arrhythmias, coma, and death.


Any medication can be toxic and potentially fatal to cats. It is important to keep all medications away from pets!

Cats are more sensitive to medications that require metabolism by the liver because they lack an enzyme that is present in other species. Therefore, cats may not tolerate some medications or treatments that dogs or other animals will.

Acetaminophen (Tylenol)—Ingestion destroys red blood cells, respiratory distress, facial edema, liver failure, and is often fatal. This medication is metabolized by the liver and is specifically toxic to cats.

NSAIDs (aspirin, ibuprofen, etc.)—Ingestion can cause gastrointestinal signs (vomiting) related to the formation of stomach ulcers. Kidney failure may also occur.

Household Products

Cleaners/Detergents—Cats are typically exposed to cleaners either through direct ingestion or indirectly by grooming the substance from their fur. Clinical signs include drooling, vomiting, and difficulty breathing.

Antifreeze—Contains ethylene glycol. Ingestion will cause acute, often irreversible, kidney failure and death.


  • Over-the-counter topical flea medications: Overexposure most often occurs when dog formulations are used on cats. Cats are extremely sensitive to permethrins because they require metabolism by the liver. Large doses ‘overload’ the liver’s ability to metabolize the chemical. Over-exposure can cause hypersalivation, tremors, seizures, and possibly death.
  • Lawn and garden products

If you discover that your cat has been exposed to a potentially toxic compound or if you are not sure if it is toxic, call your veterinarian immediately.

You may also consult the Pet Poison Helpline at 1-800-213-6680 or the ASPCA Poison Control Center at 1-888-426-4435.

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