At holiday time, we often hear warnings to keep our animals and toddlers away from poinsettias. If eaten, we’re told, the lovely looking leaves could result in plant poisoning.
Few people know that more than 700 plant species in North America are poisonous. Fortunately, only a small number of plants cause serious poisoning or death, and informing ourselves about the toxic potential of the plants in our garden and home can help prevent both us and our animals from getting plant poisoning.
Every plant possesses a different chemical make-up, often a combination of poisonous and non-poisonous compounds. A poisonous substance may be concentrated in only certain parts of the plant, e.g. the fruit, seeds, flower, leaves or roots, and sometimes poisons in plants are actually the byproduct of plant metabolism.
When a potentially harmful plant substance is consumed in small amounts, the body normally eliminates it. Animals differ in their level of tolerance for particular poisons, so it is best to avoid any plants which contain high concentrations of a poisonous substance. Even low concentrations of a plant poison can pose a health risk if it is consumed in a large enough quantity.
The effect of a poison depends on many variables. What may be poisonous to a human, for example, may not be for a bird. The animal’s age and state of health determine how well an animal can tolerate a poison. The season, the humidity and other environmental factors, as well as the growth stage of the plant (e.g. ripe or unripe fruit), can also have a bearing on the toxicity of a particular plant.
How to prevent plant poisoning
- Correctly identify all plants and determine their toxicity before they are placed in your animal’s environment. Place potentially poisonous plants well out of the reach of your animal or in a part of your home not occupied by the animal.
- Make sure that any plant that comes into contact with your animal’s mouth and paws or beak and claws is safe to hold, chew or ingest.
- Certain poisonous plants or plant parts can be rendered harmless through the cooking process. Boiling lima beans in an uncovered pot, for example, will release the hydrogen cyanide gases. Likewise, boiling grains and potatoes for at least 10 minutes destroys the toxic lectins.
- Never harvest plants, branches, flowers and berries from the roadside or near major traffic areas as these plants accumulate heavy metals, such as lead and cadmium.
- Avoid plants that have been treated with pesticides and herbicides.
- Ensure that food is free from molds, fungi and mildews. Store foods such as nuts, grains and seeds in a cool, dry place.
How to recognize the signs of plant poisoning
The ingestion of a poisonous plant substance can cause liver or kidney damage, high blood pressure, gastrointestinal disturbances, such as vomiting, diarrhea and constipation, and disorders of the immune, circulatory and nervous (coma, convulsions, muscular twitching, lack of coordination) systems. The effects of poisoning can prevent cell division, lower blood sugar levels, increase heart rate, bring on shock, and interfere with normal blood clotting. Substances found in certain plants can cause a variety of skin reactions simply from physical contact with them: pain, redness, blistering, swelling, and nasal or eye irritation. If other plants are either eaten or touched, they can cause an allergic reaction: respiratory distress, mouth and throat irritation, and even death.
Steps to take if your animal has been poisoned
- Identify the plant species in question.
- Call your local veterinarian immediately and seek medical aid and advice.
- Keep your animal warm, comfortable and as stress-free as possible.
- If the animal vomits, save a sample and take to your veterinarian’s office for examination.
- Take the plant to the veterinarian’s office for further inspection and identification.
In spite of all that is known about plant chemistry, there is still so much more to discover. While some plants are indeed poisonous, many plants are used for medicinal purposes as well as for their nutritive value. The continued study of plants and their multiple uses and benefits will provide us with even more knowledge to better the health of our animals.
Poisonous Plants List – from A-Z
The following is a list of some potentially poisonous plants. Be sure you correctly identify all plants in your animal’s environment. Keep those plants that are known to be poisonous out of the reach of your animal. Remember that homeopathic remedies containing any of the following do not present a health risk.
Acokanthera (all parts toxic except ripe fruit)
Angel’s Trumpet (leaves, seeds, flowers)
Apricot (pits, leaves, bark)
Apple (seeds, leaves, bark)
Avocado (pit, leaves, stems, unripe fruit)
Balsam Pear, Bitter Melon
Bird of Paradise (seed pods, flowers)
Catclaw Acacia (twigs, leaves)
Cherry (pits, leaves, bark)
Cycad or Sago Cycas
Dieffenbachia (dumb cane)
Eggplant (unripe/overripe fruit, leaves)
Elderberry (roots, leaves, stems, bark)
Elephant’s Ears or Taro
Euonymus (fruit, bark, leaves)
Holly (leaves, berries)
Ivy (Boston, English and some others)
Jessamine, Yellow (leaves, stems)
Jimsonweed (leaves, seeds, flowers)
Morning Glory (seeds)
Peach (leaves, pit, bark)
Pear (leaves, seeds, bark)
Plum (leaves, pit, bark)
Potato (sprouts, leaves, berries, green tubers)
Tomato (stems, leaves)