Cats and Lilies

Mary Malucci
Apr 13, 2024
5 min read

Updated: Dec 24, 2024

Many of the ornamental plants we grow in our gardens or indoors as houseplants are poisonous to our pets when chewed on or eaten. Some plants are so toxic that even a small exposure can be deadly. Often the first signs you’ll see if your pet has ingested a poisonous plant are excessive drooling and vomiting.

For cats, the plants of most concern are true lilies. Lilies from the genus Lilium, which includes Asiatic, Stargazer, Tiger and Easter lilies, or Daylilies, from the genus Hemerocallis, are so poisonous, small ingestions of leaves, petals or pollen can result in severe kidney failure. Even the water in the vase the flowers were kept in can be toxic. If you see or suspect your cat has ingested any amount of a true lily, seek treatment immediately. If your cat likes to nibble on plants, it is best to keep the true lilies out of your home and yard.

In dogs, lily ingestions appear to be limited to gastrointestinal distress, like drooling, vomiting and diarrhea.

Related to true lilies (Lilium) is the Autumn crocus (Colchicum autumnale), which is highly toxic to both dogs and cats. Commonly referred to as Naked Ladies, these plants contain a poison called colchicine, which can cause severe vomiting, diarrhea with blood, liver and kidney failure, heart arrhythmias, respiratory failure, bone marrow suppression and sudden death. Symptoms may appear immediately or days later.

Many of our favorite spring blooming bulbs are also poisonous. All parts of these plants are toxic. Mercifully, the poisons are most concentrated in the bulbs. These plants will cause tissue irritation to the mouth and esophagus, resulting in excessive drooling, vomiting and diarrhea. For pets who chew on or ingest small amounts of leaves or petals, the symptoms will likely stop there and be temporary. Rinsing the pet’s mouth with cool water helps.

Extremely large ingestions, especially of bulbs, may result in cardiac abnormalities, low blood pressure and respiratory changes. Some bulbs may even cause central nervous system effects like tremors or seizures. Dogs who love to dig and eat their treasure are most at risk here. Dogs who swallow large chunks of bulbs may also be at risk for intestinal blockage. Tulips are in the same family as true lilies. Hyacinths contain toxins similar to tulips. Daffodils, from the genus Narcissus, are in the same family as Amaryllis, also poisonous, and contain an alkaloid called lycorine, which causes vomiting and can lead to severe cardiac and respiratory effects.

Another very poisonous spring bloomer is the Lily of the Valley. From the genus Convallaria, they contain cardiac glycosides similar to digitalis (from Foxglove Digitalis purpurea, highly toxic) that work by affecting the electrical activity of the pet’s heart. Symptoms will include vomiting, diarrhea, low blood pressure, decreased heart rate, severe cardiac arrhythmias and possible seizures and death.

As we continue around the garden, let’s discuss some of our favorite spring blooming bushes. All parts of Oleander (Nerium oleander) are considered toxic and contain cardiac glycosides, which will cause symptoms like those seen with Foxglove or Lily of the Valley. In cats, the symptoms can include weakness, tremors and transient blindness. Kalanchoe (Kalanchoe spp) is a popular flowering succulent that contains cardiac glycosides also.

Azaleas (Rhododendron spp) contain grayanotoxins, which affect muscle function. Small ingestions of a few leaves can be potentially fatal. Symptoms will start with drooling, vomiting and diarrhea. If left untreated, the pet will fall into a coma and die from cardiovascular collapse.

While they do not bloom, many species of Yew (Taxus spp) are popular landscape bushes because of their evergreen hardiness. The most toxic species to dogs are Japanese yew (Taxus cuspidate), English yew (Taxus baccata), and Chinese yew (Taxus chinensis). The poisons, Taxine A and B, affect the dog’s heart and central nervous system. Just chewing on a yew branch causes signs of poisoning in our dogs, like drooling, vomiting, diarrhea, dilated pupils, trouble breathing, tremors, seizures, sudden changes in heart rate and blood pressure and sudden death. Yew is extremely bitter so poisoning in dogs is rare.

Chrysanthemums are popular garden flowers that bloom in late summer and fall. These are the plants from which pyrethrin is derived, a commonly used insecticide in flea control products. Dogs tolerate the pyrethrins in flea products well. Cats are more sensitive to it and sometimes show signs of toxicity even when a product is applied according to label directions. The most common symptoms will be drooling, vomiting and diarrhea. Very large ingestions may cause a lack of coordination and impaired balance.

English Ivy (Hedera helix) is a popular ground cover in many gardens. The leaves contain more of the toxins than the berries. The poisons in English Ivy are called triterpenoid saponins, which cause oral irritation, drooling, vomiting, abdominal pain and possibly diarrhea. Moving indoors from the garden, Snake plants (Sanseveria) and Cyclamen (Cyclamen spp) are very popular house plants that contain saponins like the English Ivy.

Now that we have moved indoors, let’s look at popular house plants that are toxic to our pets. Several plants produce insoluble calcium oxalate crystals for defense against browsers, like deer. These crystals will cause oral irritation, drooling and vomiting. Large ingestions may cause burns in the mouth and difficulty swallowing. The crystals don’t cause organ damage because they are not absorbed systemically. Despite their common names, Peace Lilies (Spathiphyllum), Calla Lilies (Zantedeschia) and Peruvian lilies (Alstroemeria) belong to different families and are not related to true lilies or daylilies. Pothos plants, either Epipremnum or Scindapsus, are popular vine house plants. Dumb cane is a common name for Dieffenbachia, which looks similar to Snake plants. Umbrella trees (Schefflera spp) and Philodendron (Philodendron spp) also contain insoluble calcium oxalate crystals.

One popular house plant is significantly more toxic than those mentioned in the previous paragraph. Sago palm is a common name for two highly toxic plants (Cycas revoluta and Zamia spp) which contain cycasin. All parts of these plants are poisonous and will cause severe liver failure in dogs. Initial signs include drooling, vomiting and diarrhea. Severe liver failure and possible central nervous system signs (weakness, ataxia, tremors or seizures) will be seen 2-3 days post ingestion. Cycasin poisoning can be fatal for cats, even with aggressive treatment.

If you suspect your dog or cat ingested any part of a poisonous plant, I strongly recommend you call either the ASPCA Animal Poison Control Center at 888-426-4435 or Pet Poison Helpline at 855-764-7661. Both of these services require a fee up front and will start a case file for your pet. Once the case file is opened, the veterinary team can call back as much as necessary for treatment guidance.

Take photos of the plant and the plant identifier tag if you still have it. ASPCA will let you email a photo of the plant to them for identification. Even if your pet isn’t showing symptoms yet, it’s best to seek care quickly. Be prepared for an emergency vet visit for your pet.