top of page

Plants Toxic to Pets

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 ingestion 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 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 neurological 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.


bottom of page