Monstera is toxic to cats and dogs. The plant sold as monstera, Swiss cheese plant, or split-leaf philodendron is Monstera deliciosa, and the ASPCA lists it as toxic to cats, dogs, and horses1. Every part of the plant carries the same toxin, so a chewed leaf, a bitten stem, or a nibbled aerial root all cause the same reaction.
Why monstera is toxic
Monstera tissue is packed with insoluble calcium oxalate crystals, called raphides, held in bundles inside specialized cells. When a cat or dog bites the plant, those cells rupture and fire the crystals into the soft tissue of the mouth and tongue like microscopic needles2. The pain is immediate, which is why most animals spit the plant out fast and rarely swallow a large amount. The toxin is mechanical, not something the body absorbs and processes, so the trouble stays where the chewing happened: the mouth, throat, and stomach.
What the symptoms look like
Signs usually appear within minutes of chewing. Watch for:
- Pawing at the mouth or face
- Excessive drooling
- Oral pain, and swelling or redness of the lips, tongue, and gums
- Vomiting
- Difficulty swallowing, or a sudden loss of interest in food and water
- Hoarse or changed vocalization from an irritated throat
The reaction is the same in cats and dogs. It tends to be more noticeable in cats because they groom and chew houseplants more readily, and because a small cat gets a larger dose relative to body weight from the same bite.
How dangerous is it, really?
For most pets, a monstera bite is painful but not life-threatening. The irritation is self-limiting and often eases within a few hours once the animal stops chewing. Deaths are very rare and generally involve a large amount swallowed by a small animal.
The case that needs a vet immediately is airway swelling. If the mouth or throat swells enough to make breathing or swallowing hard, that is an emergency, not a wait-and-see. Also call your vet if vomiting is repeated, if your pet cannot keep water down, or if you are unsure how much was eaten.
One point of confusion worth clearing up: monstera is not a true lily, and it does not cause the fatal kidney failure that true lilies (Lilium and Hemerocallis) cause in cats. Those are a separate, far more dangerous category. Monstera is in the same irritant group as pothos, philodendron, peace lily, and dieffenbachia, all of which share the calcium oxalate mechanism.
What to do if your cat or dog chews a monstera
Stay calm and act in this order:
- Take the plant away and remove any pieces left in the mouth.
- Wipe the mouth and gums with a damp cloth to clear lingering crystals.
- Offer fresh water. Something cold, or a little milk if your pet tolerates it, can soothe the burning.
- Watch for the emergency signs above, especially any change in breathing.
If symptoms are more than mild irritation, or you are worried about the amount eaten, call your veterinarian, an emergency animal hospital, the ASPCA Animal Poison Control Center at (888) 426-4435, or the Pet Poison Helpline at (855) 764-76613. The two helplines run 24 hours and may charge a consultation fee. Do not induce vomiting unless a professional tells you to, since bringing the crystals back up can irritate the throat a second time.
Cat- and dog-safe plants to grow instead
If you want the same leafy, tropical look without the risk, these plants are all listed non-toxic to cats and dogs by the ASPCA4:
- Spider plant (Chlorophytum comosum)
- Parlor palm (Chamaedorea elegans)
- Boston fern (Nephrolepis exaltata)
- Prayer plant (Maranta leuconeura) and calathea
- Areca palm (Dypsis lutescens)
- African violet (Saintpaulia)
- Haworthia, a safe succulent alternative to aloe
You can also keep a monstera and place it out of reach: a high shelf, a hanging position, or a room the pets do not enter. The plant is only a hazard when an animal can bite it.
How Ezina handles this
Ezina flags pet toxicity on the plants in its catalog, sourced from the ASPCA database and shown with the same visibility as light and water needs, so you know before a plant comes home. Toxicity is a fact about a plant, not a warning we bury. The app is in closed alpha now, launching in early 2027.
The short version: monstera is toxic to cats and dogs, the usual outcome is painful mouth irritation rather than a tragedy, and the fix is to keep it out of reach or grow one of the safe plants above.