Cat toxicity hub — lilies, NSAIDs, and the cat-specific things
Cats have different toxic thresholds than dogs — generally lower, sometimes dramatically so. This hub covers the cat-specific exposures (lilies, acetaminophen) + the cross-species toxins (chocolate, xylitol, onion, garlic) where the dog calculator math applies with adjusted thresholds. Mid-emergency? Call a hotline now.
All cat toxicity references
Binary — ANY exposure is emergency
True lilies (Lilium, Hemerocallis) cause acute kidney failure in cats, even from pollen or vase water. No safe dose — every exposure is an emergency, and treatment started within the first 18 hours gives the best outcome.
Toxic from about 10 mg/kg — one 325 mg tablet is roughly 80 mg/kg for a 4 kg cat
Cats are deficient in the glucuronidation pathway humans use to safely metabolize acetaminophen. The toxic metabolite damages red blood cells (methemoglobinemia) and the liver. There is no safe dose for a cat.
Precautionary — any exposure is hotline-worthy
Far less studied in cats than in dogs, so the precaution is borrowed from dogs, where tartaric acid is the leading suspect for the kidney injury. Cats rarely eat grapes on purpose; exposures usually involve raisin bread or a dropped grape that got played with.
No safe amount on skin or fur — keep concentrated oils away
Cats clear phenols and many oil compounds poorly. Tea tree, eucalyptus, peppermint, citrus, pine, wintergreen and ylang-ylang are the usual culprits, on the skin or licked off fur. Diffusers add a breathing risk, especially for cats with asthma.
No validated cat threshold — call for any amount
Theobromine is toxic to cats too, but cats rarely eat chocolate because they cannot taste sweetness. The dog calculator shows the mg/kg dose, which is useful to tell the hotline — but its severity bands are for dogs, not cats.
Poorly studied in cats — call to be safe
The limited research suggests cats are much less sensitive to xylitol than dogs, but the evidence is thin. If your cat ate sugar-free gum, mints or baked goods, call a vet or poison line rather than relying on the dog bands.
Per-toxin thresholds
Onion, garlic, chocolate, xylitol, grapes — all toxic to cats too, usually at lower absolute doses because cats are smaller.
EMERGENCY / CALL VET / MONITOR
60-second triage. Has a cat-specific section covering lily emergencies and the acetaminophen warning.
Safe / Caution / Toxic per food, BOTH species
Searchable safety ratings — every food rated separately for dogs AND cats. The cat ratings are often more restrictive (e.g., lily of the valley, all true lilies).
Choosing the right tool for a cat
Most of the calculators on this site were built around dog dose data, and for cats that matters. Use them to work out how much your cat may have taken in mg/kg — that number is useful to whoever you call — but don't treat a dog severity band as an all-clear for a cat. Four exposures should go straight to a phone call or an emergency vet without any calculating: any part of a true lily (including pollen or vase water), any acetaminophen, any dog flea product containing permethrin, and any concentrated essential oil on the skin or fur. When you call, have your cat's weight, the product or plant (a photo helps), and the time of exposure ready.
Why cats need separate consideration
Cats have a deficient glucuronyl transferase enzyme system — the liver pathway humans use to detoxify many common drugs. This is why acetaminophen (Tylenol) is toxic to cats from about 10 mg/kg (a single regular-strength tablet can be fatal). It's why aspirin, when a vet prescribes it for a cat at all, is given every 48–72 hours rather than daily. It's why many essential oils that humans tolerate cause cat-specific liver toxicity.
On top of the metabolic differences, cats encounter a unique exposure: true lilies (Lilium and Hemerocallis genera). The toxin is unknown, there is no known safe dose, and the kidney failure that follows is often fatal unless treatment starts early — ideally within the first 18 hours. Dogs are unaffected by the same plants. This single risk is why cat households should be lily-free.
The cat-specific things dogs don't deal with
- True lilies (acute kidney failure from pollen alone — see emergency guide)
- Acetaminophen (Tylenol) — toxic to cats from about 10 mg/kg, a fraction of the dose that harms most dogs
- Essential oils — tea tree, eucalyptus, citrus, peppermint, pine, cinnamon all cause cat-specific liver toxicity
- Permethrin (in many dog spot-on flea products) — acutely toxic to cats; tremors and seizures usually start within hours and need urgent treatment. See flea + tick guide.
- Onion / garlic — cats' red blood cells are more easily damaged by these than dogs', so smaller amounts matter (including onion powder in baby food and gravy)
- Aspirin — cats clear it several times more slowly than dogs; even "low-dose" aspirin can cause toxicity if given on a human schedule
Sources: ASPCA APCC; Pet Poison Helpline; AAFP feline toxicology references; Merck Veterinary Manual — Cat-specific toxicology section. US-baseline sources; UK ISFM + Australian ASAVA publish equivalent feline-toxicology guidance.
Cat toxicity — frequently asked
What's the single most lethal exposure for a cat?
True lilies (Lilium and Hemerocallis genus — Easter, Tiger, Asiatic, Stargazer, Daylily). Pollen alone is enough to cause acute kidney failure. There's no dose threshold; any exposure is an emergency. Cats treated with decontamination and IV fluids within about 18 hours usually do much better than cats treated later. Acetaminophen (Tylenol) is a close second — toxic from about 10 mg/kg, so a single regular-strength tablet can be fatal for a small cat.
Are cats more sensitive than dogs to most toxins?
For most household toxins — yes. Cats have a deficient glucuronyl transferase enzyme system, meaning they can't metabolize many drugs (acetaminophen, aspirin, some essential oils) as efficiently as dogs or humans. Lower body weight also means a "small" dose is proportionally larger. Dog thresholds do not transfer to cats in either direction (xylitol, for example, appears far less dangerous to cats), so for a cat the safe default is to call a vet or hotline rather than apply dog numbers.
Why isn't there a cat-specific chocolate calculator?
Cats rarely ingest chocolate voluntarily — they lack sweet-taste receptors. When cat-chocolate poisoning happens, it's usually via cross-contamination (cat eats a frosted cookie crumb off the floor, licks a chocolate-coated wrapper). The dog chocolate calculator gives you the methylxanthine dose in mg/kg, which is useful information for the hotline, but there is no validated cat threshold to compare it against. For a cat, call for any amount.
What about essential oils?
Many essential oils are toxic to cats: tea tree, eucalyptus, citrus oils, peppermint, cinnamon, pine, and others. Cats can't process the phenols and monoterpenes that humans tolerate. Even diffused oils in a room a cat lives in can cause respiratory irritation + liver stress. Rule: keep essential-oil products out of homes with cats unless you've cleared each specific oil with a vet.
My cat ate part of a lily — but seems fine. Can I wait?
No — "seems fine" at hours 0-6 is exactly what acute lily toxicity looks like in cats. The kidney damage develops on a delay — by the time symptoms show (vomiting, lethargy, decreased urine output at 24-72 hours), kidney values are already elevated and treatment is much harder. Go to a vet now. See the cat-lily emergency guide for the full action plan.
How much do the hotlines cost for cat-toxicity calls?
Same as dog calls: ASPCA APCC (888-426-4435) is $95 per case; Pet Poison Helpline (855-764-7661) is $85 per case; UK VPIS is £35; Australia's Animal Poisons Helpline (1300 869 738) and New Zealand's National Poisons Centre (0800 POISON / 764 766) are free for owners. Both ASPCA and PPH have veterinary toxicologists with specific cat-toxicity expertise on staff.