Pets and Toxic Plants

Weed Lethal Foliage from Your Home

If you’ve got a green thumb or even the slightest fondness for keeping houseplants around, then it’s time to take a serious inventory of the foliage inside and around your home. Pet Poison Helpline, the nation’s largest animal poison control center, has identified more than 200 common plants that are dangerous to pets.

The effects of these poisonous plants can range from nausea to death. Vulnerability to plant toxicities depends on pet species, amount ingested, and the size of your pet.

Plant Smarts

Plants and flowers that pet owners should educate themselves about are those that are both common and deadly, says Dr. Ahna Brutlag, a veterinary toxicologist at Pet Poison Helpline. While many plant nurseries do a reasonable job of tagging plants which are toxic to people such as foxglove and castor beans, they rarely warn about plants toxic to pets. The two most common examples are lilies (Lilium and Hemerocallis species) which are highly toxic to cats (only) and sago palms/Cycads which are highly toxic to dogs (and other pets or people should enough be ingested).

Both true lilies (Lilium species) and day lilies (Hemerocallis species) come in several colorful varieties with characteristic trumpet shaped flowers and both cause rapid onset of kidney failure in cats. These are extremely common plants. For example, star gazer lilies are a staple in cut flower bouquets due to their compelling scent, longevity, and affordability. Lilies may also be sold as potted plants (e.g. Easter lily) or for outdoor perennial gardens (e.g. tiger lilies). Day lilies (Hemerocallis species) are typically sold only for outdoor planting. If you share your home with cats, it’s critical that you do not bring these flowers inside and ensure cats cannot access them outdoors. Exposure to any part of the plant, including leaves, flowers, pollen, or even the water from the vase may result in kidney failure. These ingestions are medical emergencies requiring immediate veterinary care. Thankfully, lilies do not appear highly toxic to other species. In fact, some species of day lilies are considered edible for people. To learn more about lily poisoning, view photos of toxic lilies, and obtain a list of safer cut-flower alternatives, visit No Lilies for Kitties.

Sago palms (also called cycads or “cardboard palms”) grow readily in the warm climates of the southern United States. These palms include plants in the genera Cycads, Macrozamia, and Zamias. Examples include Cycad (Cycas cirinalis), Japanese cycad (Cycad revolute), Coontie plant (Zamia pumila), and Cardboard palm (Zamia furfuracea). Over the past decade, they have become popular as potted house plants and are now sold in all parts of the US on a year-round basis. All parts of sago palm are considered poisonous, with the seeds (nuts) being the most toxic part of the plant. All ingestions are considered emergencies as liver failure can rapidly occur. Even with excellent medical care, studies have shown the prognosis of survival for poisoned dogs is only 50%. 

Thankfully, on the whole, there are relatively few house plants or cut flowers that are highly toxic to pets. Therefore, just knowing the most common is often enough to keep pets safe. See below for a pertinent listing.

In some cases, the entire plant is toxic but in others, it may just be the bulb, stem, leaf or petal of the plant that is poisonous. You can consult with Pet Poison Helpline or your veterinarian if you have any questions about a particular plant or the portion of a plant that may be toxic.

Top Plant Toxins Checklist

Highly toxic plants for both cats and dogs include those listed below. It’s strongly recommended to exclude these from your home or flowerbeds to protect pets. According to Pet Poison Helpline, the most common poisoning scenarios involve cats ingesting cut-flower bouquets or potted Easter lilies inside the home; dogs chewing on sago palms, both inside and outside the house; and new puppies chewing on outdoor plants.

• Autumn crocus (Colchicum autumnale) – unlike their more popular spring cousins, these crocuses bloom in the fall and contain cholchicine. Ingestion can result in severe gastrointestinal signs (e.g., drooling, vomiting, gastrointestinal bleeding, bloody diarrhea, etc.), liver and kidney damage, respiratory failure, central nervous system signs (e.g., seizures), and even death. Signs may be seen immediately but can also be delayed for days.
• Azaleas (Rhododendron species) – These stunning springtime bloomers contain toxic substances called grayanotoxins. All parts of the plant are considered poisonous. When ingested, clinical signs include gastrointestinal signs (e.g., drooling, vomiting, diarrhea, abdominal pain, lack of appetite), changes to heart rate, rhythm and blood pressure, and central nervous system signs (e.g., depression, tremors, transient blindness, seizures, coma, etc.).
• Castor beans (Ricinus communis) – This dramatic beauty can grow to more than 6 feet tall and produces distinctive, red “hairy” seed pods. Both the leaves and seeds contain the potent toxin, ricin, a poison with a long and infamous history. Fans of Breaking Bad will likely remember this one.
• Daylilies (Hemerocallis species) – These plants, while edible for people, can be deadly for cats. See above for more detail.
• Foxglove (Digitalis species) - The toxin in this plant, digitalis, is known for its effects on the heart, and is the foundation of digoxin, the common heart medication used in both human and veterinary medicine. All parts of the plant are generally considered toxic – even the water in the vase has been reported to cause poisoning. Clinical signs from ingestion include changes to heart rate and rhythm electrolyte abnormalities (e.g., a life-threatening high potassium level), gastrointestinal signs (e.g., nausea, drooling, vomiting, etc.), or central nervous system signs (e.g., dilated pupils, tremors, seizures). In severe cases, an expensive antidote used in human medicine can be used.
• Grapes (Vitis species) – All grapes and raisins, seeded and seedless, organic and conventionally grown, can cause kidney failure in dogs. The toxin remains unknown although speculation that it may be tartaric acid, a natural component found in grapes, tamarinds, and cream of tartar, has been proposed.
• Lilies (Lilium species) – These colorful plants are commonly found in floral bouquets and outdoor gardens. Unfortunately, just small ingestions can be deadly for cats. See above for more detail.
• Lily of the valley (Convallaria majalis) – This is one of the many plants that contain the name ‘lily’ but are not a true lily. Therefore, they do not cause kidney failure in cats. Instead, this plant is similar to foxglove in that contains toxins that affect the heart.. When dogs or cats ingest lily of the valley, severe clinical signs can be seen, including vomiting, diarrhea, a decreased heart rate, cardiac arrhythmias, and possibly seizures. Poisoning has been reported in both pets and people drinking water from the vase holding these flowers.
• Mountain laurel (Kalmia species) - Mountain Laurel also contains grayanotoxins, see azaleas and rhododendrons above.
• Oleander (Nerium oleander) – Oleander grows readily in warm locations in the US such as California and Texas. It grows both in the wild and as landscaped plants in backyards. Like foxglove and lily of the valley, oleander contains a cardiac glycoside—oleandrin—that affect the heart. All parts of the plant are toxic, including water leaves in which leaves have been floating. Ingestion of just 1-2 leaves can be toxic to cats or dogs.
• Rhododendrons – See azaleas (above)
• Sago palms (Cycas revolute) – This common subtropical plant is used extensively in backyard or commercial landscaping and often causes poisoning in dogs. See above for more detail.
• Yesterday, Today, and Tomorrow (Brunfelsia species) – This perennial tropical shrub is also called Lady-of-the-Night or Morning-Noon-and-Night. In the US, it grows in the southern most regions (USDA Zones 9-11) although some grow farther north as an indoor/outdoor potted plant. It most commonly causes neurologic signs, making dogs very sensitive to simulation from touch, sound, or light which can result in tremors and seizures. Additionally, a decrease in activity, paralysis and low blood pressure may occur.
• Yew (Taxus species) – Japanese yews are generally considered the most toxic of this species and are commonly grown as shrubs in the northern half of the US and into Canada.  All portions of the plant are toxic except for red flesh of the aril (often called a “berry”), even the small seed inside the aril. The primary toxin—taxine--causes a decrease in heart rate and blood pressure, as well as possible changes to heart rhythm and neurologic signs including difficulty walking, tremors and seizures. Poisoning in horses or livestock occurs when people trim yew shrubs and throw the clippings into the pasture.

In An Emergency

“As a general rule, if you even think your pet nibbled on a potentially poisonous plant, call Pet Poison Helpline or your veterinarian immediately because some of these toxins act very quickly,” says Dr. Brutlag.

Also, the sooner treatment can be started, the better the prognosis. For example, following ingestion of some toxic plants, there is a small window of time where vomiting can be safely and effectively induced, possibly even at home. The experts at Pet Poison Helpline will help guide you or your veterinarian through appropriate treatments. When calling, it’s helpful to have the name of the plant and an estimate of how much your pet ingested. Taking photos of both the plant and the portions that were eaten can also be helpful to confirm identification of the plant and the portion consumed.

About Pet Poison Helpline

Pet Poison Helpline is a 24/7 animal poison control service available for pet owners and veterinary professionals who require assistance with treating a potentially poisoned pet.  Their experts can consult on all toxins and all species.  Pet Poison Helpline is the most cost-effective animal poison control service in North America, Canada and the Caribbean. Pet Poison Hotline is happy to partner with Nationwide and is available for free to Nationwide policy holders. You can reach them at 855-289-0358.