Poisonous Plants

Every year, animal poison control hotlines field dozens of questions regarding poisonous plant exposure. Dogs and cats frequently chew on or ingest plants’ foliage and flowers found both in and around the home. While most ornamental plants are innocuous, there are certainly many which do contain toxins harmful to pets. The effects of these toxins can range from minor irritation in the mouth to major organ failure.

Cats are often drawn to spiky-leaved plants like the dracaena or new cut flowers brought into the home. It is not the smell which attracts them, but rather the crunch of the leaves. Dracaenas contain calcium oxalate crystals which cause irritation to the mouth’s lining so excess salivation is seen. Dogs and especially puppies explore their world with their mouths and so are more likely to ingest toxic plants. For example, be extremely wary of the sago palm. It’s a tropical ornamental featured for its unusual foliage. While all members of this cycad family of plants are toxic, this particular one is especially harmful to the liver. Signs of toxicity include vomiting and diarrhea but can progress to seizures and liver failure.

Also indoors, the lovely kalanchoe and cyclamen can cause severe gastrointestinal upset by damaging the gut’s lining. In addition, these plants also contain cardiotoxic substances which cause irregular heart rate and rhythms. Of course, oleander and foxglove are also well known for their adverse effects on the heart. To keep pets safe, try to display indoor plants out of the reach of cats, and avoid placing harmful plants around dog pens or yards.

There are species differences in susceptibility to toxins in plants. Cats, for instance, are very likely to have kidney problems-which can be fatal, from ingestion of lilies. The toxic principal does not affect dogs nearly so severely. Yet dogs will suffer kidney failure from an overdose of grapes or raisins. We often forget that the leftover fruit or vegetables on our plates are plants which still contain active compounds. Onions and garlic are not innocuous. These contain sulfoxides, chemicals which cause an anemia due to red blood cell destruction. And don’t toss macadamia nuts to your dog either. They have a compound which causes an inability to stand or use the hind limbs. Fortunately, the problem is reversible.

Factors which affect how toxic a plant is include the age of an animal, his or her size and the vigor of the plant. Obviously, a tiny chihuahua is more likely to experience GI problems from onions than a larger Labrador. And how healthy a plant is may influence how much toxin it will produce. Hardy plants are better able to elaborate toxic
compounds.

If you catch your pet in the act of ingesting a poisonous plant, you can induce vomiting with either syrup of ipecac or hydrogen peroxide. Call you veterinarian for the appropriate dose. The Animal Poison Control Center at the University of Illinois states that the most severe illnesses come from the following plants: lilies, azaleas, oleander, sago palm, castor bean, kalanchoe and autumn crocus. This list is by no means complete. Thousands of plants contain active substances which can cause harm. There are several hotlines an owner can call to inquire if there’s a problem. These centers have become overwhelmed with increasing numbers of calls so there is usually a fee for a veterinary consult. Have a credit card handy if you call. The Animal Poison Control Center is 888-426-4435 and the Pet Poison Helpline is 800-213-6680.