Plant poisoning is caused by chemicals in plants that have undesirable affects upon animals and humans. Some poisons must be ingested whereas others, such as chemicals in poison-ivy, only require contact to elicit response in sensitive humans. Some chemicals must be modified before they are poisonous to animals, such as prunasin and other cyanogenic glycosides. These chemicals must be hydrolyzed by plant enzymes or by rumen organisms.

Plants basically poison on contact, ingestion, or by absorption or inhalation. They cause painful skin irritations upon contact, they cause internal poisoning when eaten, and they poison through skin absorption or inhalation in respiratory system. Many edible plants have deadly relatives and look-alikes. Preparation for military missions includes learning to identify those harmful plants in the target area. Positive identification of edible plants will eliminate the danger of accidental poisoning. There is no room for experimentation where plants are concerned, especially in unfamiliar territory.

Lots of plants are poisonous or capable of causing highly allergic reactions. Some will also pierce you with their sharp spines. Few actually do lasting harm but some should be treated with care and respect. Garden and household chemicals, fires, backyard swimming pools and even ladders are far more dangerous backyard hazards for children than plants.

Who’s at risk?

Children that are crawling or toddling, particularly around twelve months of age, are most at risk of eating strange bits of plants. To reduce the likelihood of babies and young children eating anything poisonous take the following precautions:

  • Teach children not to eat anything straight from a plant or bush.
  • Fence off or remove known poisonous or dangerous plants (see list).
  • Keep the Poison Information Centre phone number 13 11 26 near your phone.

Symptoms to recognise

Symptoms of poisoning from plants can include:

  • vomiting.
  • stomach cramps.
  • irregular heart beat.
  • burning to the mouth.
  • convulsions (fits).

The type and severity of symptoms will vary according to the type of plant eaten, the amount swallowed and the size of the child. The most common problems are stinging around the mouth and skin allergies.

There are no common characteristics of form, colouring, odour or taste, which distinguish a poisonous or harmful plant from a non-poisonous plant. But as a general rule of thumb, plants with a bitter taste, funny smell, milky sap or red seeds or berries may be poisonous.

To avoid poisoning, we need to learn to recognise and avoid poisonous plants so that we can teach our children to also avoid poisonous plants.

Most Common Poisonous Plants


Ingestion of Cannabis sativa by companion animals can result in depression of the central nervous system and incoordination, as well as vomiting, diarrhea, drooling, increased heart rate, and even seizures and coma.

Sago Palm

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, diarrhea, depression, seizures and liver 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, severe kidney damage could result.

Tulip/Narcissus bulbs

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


Members of the Rhododenron spp. contain substances known as grayantoxins, which can produce vomiting, drooling, diarrhea, weakness and depression of the central nervous system in animals. Severe azalea poisoning could ultimately lead to coma and death from cardiovascular collapse.


All parts of Nerium oleander are considered to be toxic, as they contain cardiac glycosides that have the potential to cause serious effects-including gastrointestinal tract irritation, abnormal heart function, hypothermia and even death.

Castor Bean

The poisonous principle in Ricinus communis is ricin, a highly toxic protein that can produce severe abdominal pain, drooling, vomiting, diarrhea, excessive thirst, weakness and loss of appetite. Severe cases of poisoning can result in dehydration, muscle twitching, tremors, seizures, coma and death.


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 intense vomiting. Fatalities have also been reported in some cases.


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


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

What To Do If Your Pet Is Poisoned

  1. Don’t panic. Rapid response is important, but panicking can interfere with the process of helping your pet.
  2. 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.
  3. 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.


Any amount of any wild mushroom is considered to be very dangerous. Please call the Poison Center immediately if anyone ingests any part of a mushroom picked from a yard or the woods. If you have any pieces of the actual mushroom that was eaten you will be asked to save it in a brown paper bag. Many mushrooms can look identical but be very different.

The following plants are dangerous, either to touch or eat. There are many other plants that can make you sick or cause a bad reaction. Because a plant is not listed here does not mean it is safe for humans or pets. The plants listed here are some of those about which the poison center often receives calls.

  • Candelabras Cactus
  • Carolina Jessamine
  • Castor Bean
  • Century Plant (Agave)
  • Chinaberry Tree
  • Dumbcane
  • Eucalyptus
  • Foxglove
  • Jimsonweed
  • Lantana
  • Mexican Bird of Paradise
  • Mistletoe
  • Oleander
  • Philodendron
  • Pothos
  • Silver Leaf
  • Texas Mountain Laurel
  • Tree Tobacco
  • Virginia Creeper
  • Yellow Oleander

Sources: ASPCA, CHW

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