Highly toxic — can be fatal
For cats, yes — dangerously so. True lilies (Lilium and Hemerocallis) cause sudden kidney failure in cats, and even tiny exposures can be fatal. This is one of the most serious plant poisonings in cats.
True lilies — including Easter, Tiger, Asiatic, Day and Stargazer lilies — are extraordinarily toxic to cats. Every part is poisonous: petals, leaves, stem, pollen, and even the water in the vase. A cat that brushes against the flower and then grooms pollen off its fur can ingest enough to cause acute kidney failure within 24–72 hours. The exact toxin is unknown, but untreated it is frequently fatal, while prompt treatment greatly improves the odds.
Cats are uniquely and severely affected — this is a feline emergency. Dogs that eat true lilies usually get only mild stomach upset, though lily-of-the-valley (a different plant) is seriously toxic to dogs’ hearts.
Treat any exposure as a life-threatening emergency. If your cat has chewed, licked, or even had pollen on its coat, call your vet or a pet poison helpline immediately — do not wait for symptoms. Treatment within the first 18 hours is far more likely to save the kidneys. Keep true lilies out of any home with cats entirely.
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General information, not veterinary advice. If your pet has eaten a toxic plant or shows symptoms, contact your vet or a pet poison helpline immediately. Full disclaimer.