Toxic — keep away from pets
Yes — philodendrons are toxic to dogs and cats, like pothos. The calcium oxalate crystals cause painful mouth burning, drooling and swelling when chewed.
Philodendrons are among the most popular houseplants in the world, and like their relatives pothos, peace lily and dieffenbachia, they contain insoluble calcium oxalate crystals. Biting the leaves releases these needle-like crystals into the mouth and throat, causing immediate pain, burning, drooling and swelling. In most cases it is not life-threatening, but significant swelling of the throat can rarely affect breathing, and the irritation may stop a pet eating or drinking for a while.
Both dogs and cats. Cats that chew trailing vines and teething puppies are the typical cases, since philodendrons are often kept as hanging plants.
Rinse the mouth and offer water or a little milk to ease the crystals, and watch for swelling. Most cases settle, but call your vet if there is marked swelling, breathing or swallowing trouble, or ongoing vomiting. A poison helpline can guide you. Keep philodendrons out of reach or choose a pet-safe plant.
Related: Is pothos toxic? · Is dieffenbachia toxic? · Is peace lily toxic?
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.