Which Houseplants Are Toxic to Cats and Dogs? A Room by Room Check

The short answer: true lilies are the emergency. Any plant in the genus Lilium or Hemerocallis, which covers Easter, tiger, Asiatic, day and stargazer lilies, can cause fatal kidney failure in cats from a dose as small as pollen groomed off a paw. Sago palm is the emergency for dogs, with a mortality rate around 50 percent even with treatment. Almost everything else on the usual scary lists, including pothos, monstera, philodendron and peace lily, causes painful but survivable mouth irritation.

That distinction matters, because treating every toxic plant as equally dangerous means people either panic over a chewed pothos leaf or, much worse, get complacent and keep a bouquet of stargazers on the kitchen counter.

The genuine emergencies

These are the plants where you call a vet immediately rather than waiting to see how your animal looks in the morning.

1. True lilies, including Easter, tiger, Asiatic, day and stargazer. Every part is toxic to cats, including the pollen and the water in the vase. Acute kidney failure can follow within 24 to 72 hours.Cats: life threatening
2. Sago palm. Not actually a palm. All parts are toxic and the seeds are the worst. Causes liver failure, with roughly half of cases fatal despite treatment.Dogs and cats: life threatening
3. Oleander. Contains cardiac glycosides that disrupt heart rhythm. A small quantity of leaf is enough.Dogs and cats: life threatening
4. Autumn crocus. Causes multi-organ damage, and signs can be delayed for days, which makes it easy to miss the connection.Dogs and cats: life threatening
5. Dieffenbachia in quantity. Usually just mouth pain, but heavy swelling of the tongue and throat can obstruct breathing in a small animal.Occasionally serious
6. Cannabis. Increasingly common as a call, and a real one. Ingestion causes ataxia, low body temperature and in bad cases seizures.Serious

If you have a cat, the single highest value change you can make is to never accept cut lilies into the house. Florists put them in almost every mixed bouquet, and a cat brushing past the anthers and then grooming has taken a meaningful dose.

The plants that hurt but rarely harm

Most of the houseplants people worry about belong to the arum family, and they all work the same way. Their tissue contains needle shaped crystals of calcium oxalate called raphides. When an animal bites down, the crystals drive into the soft tissue of the mouth and release an irritant.

The result is immediate and dramatic: pawing at the mouth, drooling, sometimes vomiting, and a very unhappy animal. It is also usually self limiting, because the pain stops them eating a second mouthful. Serious cases are rare and involve swelling that interferes with breathing or swallowing.

This group covers a large share of the plant shop: pothos, all the philodendrons, monstera, peace lily (which is not a true lily and does not cause kidney failure), dieffenbachia, calla lily, anthurium, alocasia, colocasia, and zz plant.

Also common and also mild: aloe vera, which causes vomiting and diarrhoea; jade plant, which causes vomiting and lethargy; snake plant, which contains saponins and causes an upset stomach; and rubber plant, whose sap irritates skin and mouth.

A room by room pass

Kitchen and dining. Cut flower arrangements are the biggest single risk in the house, because they arrive unannounced as gifts and often contain lilies. Check every bouquet before it goes in a vase, and remember the vase water itself is contaminated.

Living room. Large floor plants are at exactly nose height for a dog and provide a climbing frame for a cat. Fiddle leaf fig, rubber plant, dracaena and zz plant are all mild irritants. The bigger practical risk is a heavy pot getting pulled over.

Bedroom and windowsills. Small trailing plants on shelves are the ones cats actually eat, because dangling leaves read as toys. Pothos and philodendron are the usual suspects. This is where a swap to a safe species pays off most.

Bathroom. Humidity lovers live here: ferns, calathea, maranta, spider plant. This is the safest room in most houses, since all of those are non toxic.

Outdoors and the garage. Sago palm in warm states, oleander in the southwest, autumn crocus in beds, and bulbs in storage. Daffodil, tulip and hyacinth bulbs are far more concentrated than the flowers, and a dog that digs is at more risk than one that grazes.

Plants that are genuinely safe

If you want green things and a cat that chews, these are the ones to buy. All are listed as non toxic to both cats and dogs.

• Spider plant. Non toxic, and cats love it, which is a separate problem. It is mildly hallucinogenic in the same loose sense as catnip, so expect it to get chewed.
• Boston fern, bird's nest fern, maidenhair fern. All safe.
• Calathea and maranta. Safe, and the patterning is the best in the trade.
• Parlour palm, areca palm, ponytail palm. Safe. Note that sago palm is not a palm and is not safe.
• Hoya. Safe, tough, and flowers eventually.
• Peperomia, African violet, orchid (phalaenopsis), Christmas cactus. All safe.

What to do if you catch them chewing

Take the plant material out of the mouth and rinse the mouth with water, or offer something cold and palatable like a little milk or wet food to flush the crystals. Do not induce vomiting unless a vet tells you to.

Then identify the plant properly before you call anyone, because the first question you will be asked is what species it was, and "a green one from Ikea" does not narrow it much. Photograph the plant and the chewed part.

In the United States, the ASPCA Animal Poison Control Center runs 24 hours on 888 426 4435, and the Pet Poison Helpline on 855 764 7661. Both charge a consultation fee. Call regardless of fee if lilies or sago palm are involved.

Identify before you buy, not after

Plant shop labels are close to useless for this. A pot marked "assorted tropical" tells you nothing about whether the thing inside will cost you a vet bill, and common names actively mislead: peace lily is not a lily, sago palm is not a palm, and there are at least four unrelated plants sold as "dumb cane".

Identium returns toxicity information alongside every identification, so you can check a plant in the shop before it comes home rather than at midnight with an unhappy cat. Photograph a leaf with the stem visible and you will get the species, not the label.