It is difficult to give concise information about plant toxicities as there are hundreds of plants that are potentially poisonous to animals. However, actual reports of animals getting seriously ill from eating plants are relatively infrequent compared to reports of poisonings from household products or drugs. The plants discussed below represent among the most dangerous of poisonous plants. You may notice the conspicuous lack of "holiday plants" among the list. Many people seem to think poinsettias, ivy and mistletoe are dangerous plants, and while these plants have toxic potential, they seldom cause serious clinical signs if eaten.

It is worth noting here that dogs and cats often vomit after chewing on plants; this probably does not represent "poisoning" or any dangerous exposure. Only severe or persistent vomiting is a danger sign in small animals. Sporadic vomiting without accompanying signs of illness (for instance, diarrhea, depression, loss of appetite) is rarely a cause for worry, whether associated with plant ingestion or not. The best advice, however, is to contact your veterinarian if you have specific concerns.

Additional Common Names: Belladonna lily, Saint Joseph lily, Cape Belladonna, Naked Lady

Toxic Principles: Lycorine and others

Common garden plants popular around Easter, Amaryllis species contain toxins that can cause vomiting, depression, diarrhea, abdominal pain, hypersalivation, anorexia and tremors.

Additional Common Names: Meadow Saffron

Toxic Principles: colchicine and other alkaloids

Ingestion of Colchicum autumnale by pets can result in oral irritation, bloody vomiting, diarrhea, shock, multi-organ damage and bone marrow suppression.

Additional Common Names: Rosebay, Rhododendron

Toxic Principles: Grayantoxin

The toxic principle interferes with normal skeletal muscle, cardiac muscle and nerve function. Clinical effects typically occur within a few hours after ingestion, and can include acute digestive upset, excessive drooling, loss of appetite, frequent bowel movements/diarrhea, colic, depression, weakness, loss of coordination, stupor, leg paralysis, weak heart rate and recumbency for 2 or more days; at this point, improvement may be seen or the animal may become comatose and die.

Additional Common Names: Castor Oil Plant, Mole Bean Plant, African Wonder Tree

Toxic Principles: Ricin, a highly toxic component that inhibits protein synthesis. Ingestion of as little as one ounce of seeds can be lethal.

Beans are very toxic: oral irritation, burning of mouth and throat, increase in thirst, vomiting, diarrhea, kidney failure, convulsions. Access to ornamental plants or pruned foliage is common in most poisonings. Signs typically develop 12 to 48 hours after ingestion, and include loss of appetite, excessive thirst, weakness, severe abdominal pain (colic), muscle twitching, tremors, sweating, drooling, loss of coordination, difficulty breathing, progressive central nervous system depression, and fever. As the syndrome progresses, bloody diarrhea may occur, and convulsions and coma can precede death.

Additional Common Names: Daisy, Mum; many varieties

Toxic Principles: Sesquiterpene, lactones, pyrethrins and other potential irritants

These popular blooms are part of the Compositae family, which contain pyrethrins that may produce gastrointestinal upset, including drooling, vomiting and diarrhea, if eaten. In certain cases depression and loss of coordination may also develop if enough of any part of the plant is consumed.

Additional Common Names: Sowbread

Toxic Principles: Terpenoid saponins

Cylamen species contain cyclamine, but the highest concentration of this toxic component is typically located in the root portion of the plant. If consumed, Cylamen can produce significant gastrointestinal irritation, including salivation, intense vomiting, and diarrhea. Following large ingestions of tubers heart rhythm abnormalities or seizures may result. Fatalities have also been reported in some cases.

Additional Common Names: Branching Ivy, Glacier Ivy, Needlepoint Ivy, Sweetheart Ivy, California Ivy

Toxic Principles: Triterpenoid saponins (hederagenin)

Hedera helix contains triterpenoid saponins that, should pets ingest, can result in vomiting, abdominal pain, hypersalivation and diarrhea. Foliage is more toxic than berries.

Additional Common Names: Mother-In-Law-Plant, Devils Backbone, Chandelier Plant, Mother of Millions

Toxic Principles: Bufodienolides

This plant contains components that can produce gastrointestinal irritation including vomiting and diarrhea, as well as those that are toxic to the heart, and can seriously affect cardiac rhythm and rate.

Additional Common Names: Easter lily, Tiger lily, Rubrum lily, Japanese show lily and some species of the Day lily

Toxicity: Non-Toxic to Dogs, Non-Toxic to Horses, Toxic to Cats

Clinical Signs: Cats: kidney failure.

Members of the Lilium spp. are considered to be highly toxic to cats. While the poisonous component has not yet been identified, it is clear that with even ingestions of very small amounts of the plant life threatening toxicity will occur. Unfortunately, all parts of the lily plant are considered toxic to cats. Within only a few hours of ingestion of the lily plant, a cat may vomit, become lethargic or develop a lack of appetite. These signs continue and worsen as kidney damage progresses. Without prompt and proper treatment by a veterinarian, the cat may develop kidney failure in 36 to 72 hours.

Additional Common Names: Indian Hemp, Hashish

Toxic Principles: Delta-9-THC (tetrahydrocannabinol)

Prolonged depression,Ingestion of Cannabis sativa by companion animals can result in depression of the central nervous system and incoordination, as well as vomiting, diarrhea, hypersalivation, sleepiness or excitation, increased heart rate, dilated pupils, low blood pressure, low body temperature, seizure, coma, death (rare).

Additional Common Names: Rose-Bay

Toxic Principles: Cardiac glycosides

Poisonings can occur from access to prunings, fallen branches, or ornamentals around horse show areas. All parts of Nerium oleander are considered to be toxic, as they contain cardiac glycosides, much like digitoxin. These chemicals have the potential to cause serious effects such as severe abdominal pain (colic), diarrhea (possibly bloody), sweating, incoordination, shallow/difficult breathing, muscle tremors, recumbency, abnormal heart function, and possibly death from cardiac failure.

Additional Common Names: Mauna Loa Peace Lily

Toxic Principles: Insoluble calcium oxalates

Spathiphyllum contains calcium oxalate crystals that can cause oral irritation, excessive drooling, vomiting, difficulty in swallowing and intense burning and irritation of the mouth, lips and tongue in pets who ingest it.

Additional Common Names: Golden Pothos, Devil's Ivy, Taro Vine, Ivy Arum

Toxic Principles: Insoluble calcium oxalates

Pothos (both Scindapsus and Epipremnum) belongs to the Araceae family. If chewed or ingested, this popular household plant can cause significant mechanical irritation and swelling of the oral tissues and other parts of the gastrointestinal tract resulting in oral irritation, intense burning and irritation of mouth, tongue and lips, excessive drooling, vomiting, difficulty swallowing.

Additional Common Names: Coontie Palm, Cardboard Palm, cycads and zamias

Toxic Principles: Cycasin

All parts of Cycas Revoluta are poisonous, but the seeds or “nuts” contain the largest amount of toxin. The ingestion of just one or two seeds can result in very serious effects, which include vomiting, melena (blood in the stool), icterus (yellow tinge to skin and mucous membranes), increased thirst, hemorrhagic gastroenteritis, bruising, coagulopathy (blood clotting problems), seizures, liver damage, liver failure, and death.

Additional Common Names: Umbrella Tree, Australian Ivy Palm, Octopus Tree, Starleaf

Toxic Principles: Calcium oxalate crystals

Schefflera and Brassaia actinophylla contain calcium oxalate crystals that can cause oral irritation, excessive drooling, vomiting, difficulty in swallowing and intense burning and irritation of the mouth, lips and tongue in pets who ingest it.

Toxic Principles: Tulipalin A and B

The bulb portions of Tulipa/Narcissus spp. contain toxins that can cause intense gastrointestinal irritation, drooling, loss of appetite, vomiting, diarrhea, depression of the central nervous system, convulsions and cardiac abnormalities.

Additional Common Names: Japanese yew

Toxic Principles: Taxine

Taxus spp. contains a toxic component known as taxine, which causes central nervous system effects such as trembling, incoordination, muscle tremors, difficulty breathing and seizures. It can also cause significant gastrointestinal irritation and cardiac failure, which can result in death.

Mushroom toxicity does occur in dogs and it can be fatal if certain species of mushrooms are eaten. Amanita phalloides is the most commonly reported severely toxic species of mushroom in the U.S. but other Amanita species are toxic.

Symptoms include Abdominal pain, drooling, liver damage, kidney damage, vomiting diarrhea, convulsions, coma, death

Don’t panic. Rapid response is important, but panicking can interfere with the process of helping your pet. Take 30 to 60 seconds to safely collect and have at hand any material involved. This may be of great benefit to your vet and/or APCC toxicologists, as they determine what poison or poisons are involved. In the event that you need to take your pet to a local veterinarian, be sure to take the product’s container with you. Also, collect in a sealable plastic bag any material your pet may have vomited or chewed.

If you witness your pet consuming material that you suspect might be toxic, do not hesitate to seek emergency assistance, even if you do not notice any adverse effects. Sometimes, even if poisoned, an animal may appear normal for several hours or for days after the incident.

Call the ASPCA Animal Poison Control Center The telephone number is (888) 426-4435. There is a $60 consultation fee for this service.

Be ready with the following information: 

• The species, breed, age, sex, weight and number of animals involved. 
• The animal’s symptoms. 
• Information regarding the exposure, including the agent (if known), the amount of the agent involved and the time elapsed since the time of exposure. 
• Have the product container/packaging available for reference.

Please note: If your animal is having seizures, losing consciousness, is unconscious or is having difficulty breathing, telephone ahead and bring your pet immediately to your local veterinarian or emergency veterinary clinic. If necessary, he or she may call the APCC.

Please call the Merrick veterinary Group at 516-379-6200 to schedule an appointment if you think your pet may have been exposed to a toxic plant.

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