Toxic to Cats: Plants, Foods and Medicines to Keep Away

The things most often behind cat poisonings are lilies, human medicines (especially painkillers, antidepressants and ADHD drugs), dog flea and tick products, household cleaners, essential oils and a short list of foods led by onions, garlic and chocolate. That is the shape of VCA Animal Hospitals' list of the top ten cat toxins of 2023, and PetMD's guide names the same groups.

Cats are harder to protect than dogs in some ways. VCA points out that they can be poisoned by swallowing something, breathing it in, or getting it on their fur and then licking it off while grooming, and that their small size and habit of hiding illness make poisoning less obvious. PetMD notes that in 2021 the ASPCA's poison control service helped 401,550 animals.

Lilies are in a class of their own. VCA ranks them the number one cat exposure of 2023, and PetMD says deaths have been reported after a cat ate only one or two pieces. True lilies and daylilies cause kidney failure; see our lily page for the timeline and treatment.

Other plants that PetMD lists as toxic to cats, each with its own page on this site:

• Can be life-threatening: lily of the valley, sago palm (the seeds are most dangerous), oleander, yew.
• Common houseplants: pothos, dieffenbachia, aloe, peace lily, English ivy, kalanchoe, cyclamen.
• Garden and cut flowers: azalea, chrysanthemum, daffodil, tulip, hyacinth, hydrangea, amaryllis, autumn crocus, castor bean.

VCA adds that Peruvian lily causes only mild, self-limiting stomach upset. Tulips are also on VCA's top-ten list, though VCA does not describe their severity relative to true lilies. For plants you can keep, see house plants safe for cats and non-toxic flowers for cats.

Medicines cause some of the most serious cat poisonings because the doses that harm a cat are tiny:

• Acetaminophen (Tylenol). VCA says just one tablet can be fatal to a cat, causing severe anaemia, breathing difficulty, swelling of the face and paws, and liver failure.
• Ibuprofen and naproxen (Advil, Motrin, Aleve). PetMD says less than half a pill can be fatal; VCA lists kidney failure and stomach ulcers. Dog NSAIDs such as carprofen and meloxicam are also on VCA's list.
• Antidepressants. PetMD says cats seem attracted to the smell or taste of venlafaxine (Effexor), making it one of the top toxins reported in cats.
• ADHD medicines (amphetamines such as Adderall): heart and nervous-system stimulation (VCA).
• Minoxidil (Rogaine hair treatments): heart failure in cats (VCA).
• Vitamin D3 in supplements, rodent baits and psoriasis creams: a life-threatening rise in calcium (VCA).
• Alpha lipoic acid supplements: low blood sugar, seizures and liver injury (VCA).

Keep pill organisers closed and pick up dropped tablets at once.

• Onions, garlic, chives, leeks, shallots and scallions. They destroy red blood cells and cause anaemia (VCA); onion and garlic were numbers three and four on VCA's 2023 list.
• Chocolate. Stomach upset plus heart and nervous-system stimulation (VCA); PetMD says dark and baking chocolate are the most dangerous because they contain the most cocoa.
• Caffeine in coffee, tea, energy drinks and caffeine tablets (PetMD).
• Grapes, raisins and currants. VCA says it is not known whether they damage cats' kidneys as they do dogs', but advises avoiding them.
• Alcohol, xylitol, spoiled or mouldy food and salt are also on PetMD's list; alcohol can cause wobbliness, disorientation and, in severe cases, seizures.

• Dog flea and tick products containing pyrethroids such as permethrin. VCA says never to put a dog product on a cat; Community Concern for Cats lists tremors and seizures.
• Household cleaners for kitchens, bathrooms, carpets and toilets: stomach upset, chemical burns, breathing problems and organ damage (VCA). Let surfaces dry and air the room before the cat comes back.
• Essential oils. VCA says a single drop of concentrated tea tree oil can poison a cat, and liquid potpourri and plug-in air fresheners can cause poisoning and burns.
• Antifreeze (ethylene glycol). The Merck Veterinary Manual gives 1 to 2 teaspoons as a lethal amount for a cat. Wipe up drips in garages and driveways.
• Heavy metals. PetMD lists zinc (including U.S. pennies minted after 1982), lead in old paint and fishing weights, and iron in supplements.
• Hydrogen peroxide. VCA warns it injures a cat's mouth, throat and stomach; do not use it to make a cat vomit.

There is no single answer, but measured by how little it takes, four stand out in the sources:

• Antifreeze: 1 to 2 teaspoons can be lethal (Merck Veterinary Manual).
• Acetaminophen: one tablet can be fatal (VCA).
• Lilies: deaths reported after one or two pieces were eaten (PetMD); pollen groomed off the fur or water from the vase can be enough (FDA).
• Tea tree oil: a single drop of concentrated oil can poison a cat (VCA).

By how often it happens, lilies top VCA's 2023 list.

The phrase is used online for several conditions rather than one agreed diagnosis. Among poisons, the two that fit it best are antifreeze and lilies, because the first signs are vague and the real damage, kidney failure, comes later:

• Antifreeze. Early signs such as vomiting, thirst and wobbliness can start within 30 minutes (Pet Poison Helpline), and the Merck Veterinary Manual says severe kidney failure usually develops within 12 to 24 hours in cats. By the time a cat looks very ill, the 3-hour antidote window for cats (Pet Poison Helpline) has usually passed.
• Lilies. The FDA describes drooling, vomiting and reduced activity in the first 12 hours, then increased urination and dehydration, then kidney failure at 24 to 72 hours.

In both cases, act on the exposure, not on symptoms: call as soon as you know or suspect contact.

The sources we checked do not give minute-by-minute timings, but they name several poisons that can kill a cat quickly or with little warning: acetaminophen (one tablet can be fatal, VCA), minoxidil (heart failure, VCA), pyrethroid dog flea products (tremors and seizures, Community Concern for Cats), antifreeze (lethal at 1 to 2 teaspoons, Merck) and lilies (kidney failure within about three days, FDA). A cat that collapses, has a seizure or struggles to breathe needs an emergency vet immediately, whatever the cause.

Anywhere from minutes to a day or more, depending on the poison:

• Antifreeze: first signs within about 30 minutes; kidney failure in 12 to 24 hours (Pet Poison Helpline; Merck).
• Lilies: early signs within 0 to 12 hours; kidney damage from 12 to 24 hours; kidney failure at 24 to 72 hours (FDA).

For many other toxins, PetMD does not give an onset time, but it stresses that the longer you wait and the more symptoms develop, the worse the outlook. The treatment windows are short: 3 hours for the antifreeze antidote in cats (Pet Poison Helpline), and the FDA says a delay of 18 hours or more after lily ingestion usually means irreversible kidney damage.

• Call first. Your vet, an emergency clinic, the Pet Poison Helpline at (855) 764-7661 or the ASPCA Animal Poison Control Center at (888) 426-4435. VCA notes that the Pet Poison Helpline charges a per-incident fee that covers follow-up calls for the case.
• Do not make the cat vomit at home. VCA and PetMD both say this; VCA warns that salt and hydrogen peroxide cause injury or poisoning. A vet can induce vomiting safely with prescription drugs.
• If the substance is on the fur: VCA suggests bathing with liquid dish soap and lukewarm water, removing the collar, and not cutting the substance out or using solvents. If you cannot bathe the cat safely, get veterinary help.
• Tell the vet when it happened, the product or plant name, how much, and what signs you have seen (PetMD). Bring the packaging or a piece or photo of the plant.
• Transport safely: VCA suggests wrapping an anxious cat in a towel and using a secure box.

Not every danger is a poison. Community Concern for Cats' list of household dangers adds string, yarn, rubber bands, hair ties and earrings that can be swallowed, shopping bag handles that can strangle, recliners, washers and dryers that cats climb into, and glow sticks, which it says cause mouth pain and foaming. It also lists plants containing calcium oxalate among its top ten toxins, for oral and stomach irritation.

Toxicity lists work by species, and many houseplants are sold under vague or shared names. Photograph each plant you own (the whole plant plus a leaf close-up) and scan it in PlantLens, then check the result against the plant pages linked above. Having the names ready also saves time on the phone in an emergency.

Research and drafting for this page were done with the help of AI, and every figure was then checked line by line against the sources listed at the end. Where sources disagree, we say so rather than pick one silently. If you find a mistake, tell us and we will correct it.