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 from pollen alone. No dose threshold — every exposure is an ER trip. 6-hour treatment window is critical.
Lethal at 10 mg/kg — a single 325mg tablet kills a 4kg cat
Cats lack the glucuronyl transferase enzyme humans use to safely metabolize acetaminophen. NAPQI metabolite causes methemoglobinemia + hepatic necrosis. No safe dose, no safe formulation.
Precautionary — any exposure is hotline-worthy
Less-studied in cats than dogs but same suspected mechanism (tartaric acid → acute kidney injury). Cats rarely eat grapes voluntarily; exposures usually via raisin-bread crumbs or grape juice cross-contamination.
~10 mg/kg theobromine for cats (half the dog threshold)
Cats are MORE sensitive than dogs but rarely eat chocolate voluntarily. Cross-contamination from a dropped piece or a child's candy is the typical route. Use the dog calculator; divide the threshold in half for cats.
50-100 mg/kg in cats
Less-studied in cats than dogs but assume same severity. Sugar-free gum, mints, peanut butter. Onset within 15-60 minutes.
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 emergency + acetaminophen warning (lethal at 10 mg/kg in cats).
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).
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 lethal in cats at 10 mg/kg (a single regular-strength tablet can kill a 4 kg cat). It's why aspirin needs 48-hour dosing intervals in cats vs 12-hour in dogs. 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, the dose-response is binary, and the kidney failure that follows is fatal without aggressive 6-hour-window treatment. 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) — lethal at 10 mg/kg in cats vs ~100 mg/kg in dogs
- Essential oils — tea tree, eucalyptus, citrus, peppermint, pine, cinnamon all cause cat-specific liver toxicity
- Pyrethrin / permethrin (dog flea-tick products) — acutely toxic to cats; seizures within 1-3 hours, often fatal. See flea + tick guide.
- Onion / garlic in lower doses — Japanese breeds (Bobtail) especially sensitive at lower thresholds than dogs
- Aspirin — cats clear it 4× slower than dogs; even "low-dose baby aspirin" can cause toxicity at human-frequency dosing
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. The treatment window is 6-18 hours from ingestion — after that, prognosis drops sharply. Acetaminophen (Tylenol) is a close second — lethal at 10 mg/kg in cats (a single regular-strength tablet can kill a 4 kg 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. The rule of thumb: assume a cat's toxic threshold is half the dog threshold, then call a hotline anyway.
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 — for a cat exposure, divide that threshold roughly in half. We may build a cat-specific version if Search Console shows real demand.
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.