Protecting Your Pets from Poisonous Plants

By Stephen T. Sinatra, M.D., F.A.C.C., F.A.C.N., C.N.S., C.B.T.

Nature possesses countless healing powers, so it’s important that we connect with it on a daily basis. That’s why I get outside as often as I can—and why my wife Jan, who’s an avid gardener, sees to it that we always have beautiful greenery outside and inside our home.

Being pet lovers, however, we have to take special care when choosing our indoor and outdoor plants, since most dogs and cats like an occasional “salad” and view their immediate surroundings as the ultimate salad bar. Consequently, Jan and I try to make sure we don’t have any poisonous plants inside or around our home. We also never use toxic chemicals on our lawn.

Why Do Dogs Eat Grass in the First Place?

We’ve all seen dogs eating grass. Even cats do it occasionally. But why is it so common to see dogs lying down—and chowing down—on the lawn? Two simple reasons.

First off, dogs are by nature omnivores, which means they need both meat-based and plant-based foods in their diet. Also by nature, dogs are scavengers and will instinctively eat just about anything around them that might help them fulfill their dietary needs.

Canines in the wild are known to eat fruits, berries, and a wide variety of other vegetation to balance their diets. So, when you see domesticated dogs eating grass, they are most often just munching on the closest available “veggie” dish to counterbalance the meat in their diets.

There also appears to be a medicinal purpose for grass eating, since dogs instinctively eat grass when their stomachs are upset. And you’ve probably noticed that lots of times after dogs eat grass, they then throw up a bit and carry on with their day. It seems that, at least for dogs, eating grass can help settle certain digestive problems.

The Health Hazards of Dogs Eating Grass

While snacking a little on your front lawn is not uncommon or inherently unhealthy for your dog, most grass these days doesn’t exactly provide a clean meal for them. Many lawns have either been directly treated with pesticides or chemical sprays, or at least come into contact with any number of toxic topical treatments, all of which can be quite damaging to your dog’s health.

In addition, grass is a popular breeding ground for intestinal parasites that can endanger your dog’s health. Parasites such as hookworms, roundworms, tapeworms, and giardia are commonly found in the grass and ultimately cause the type of digestive distress that drives many dogs to eat grass in the first place.

Since outdoor grass can harbor so many hazards for your dog, it’s safest to limit the outside grass eating as best as you can and simply offer up some veggies with dinner to help balance his or her diet. Dogs often love broccoli, grated carrots, and string beans. (Just follow these guidelines for the foods you should never feed your pets.) Or some experts even suggest growing an indoor grass garden in a small tray that your pets can safely graze on when they crave a salad.

Also keep in mind that dogs may be less inclined to eat grass in the first place if their tummies feel settled. Treating your dog to a good probiotic supplement (one that also contains soluble prebiotic fiber) should certainly help keep his or her digestive tract running smoothly. Another option would be to try a dog supplement designed to promote better breath and detoxify the digestive system with plant ingredients such as parsley, mushroom, and yucca.

Pets & Poisonous Plants

Unfortunately, your pets aren’t only eyeing the lawn for a tasty treat. Dogs and cats alike are inclined to nibble on just about any plants they encounter—both inside and around your home.

The good news is that pets typically don’t eat enough of your landscaping or house plants to cause serious health concerns. That said, eating any plant material can cause mild gastrointestinal distress, vomiting, and diarrhea in both dogs and cats. Which is why it’s best to keep houseplants out of reach and to try to keep your pets out of your garden when unsupervised.

Of course, there is no way to completely safeguard your pets from the plants you have inside and surrounding your house. It is, therefore, critical to know which plants are truly poisonous plants when it comes to your pets, so that you can exclude them from your property completely.

Helping You Identify Poisonous Plants

It’s nearly impossible to know every single type of vegetation that could be toxic to our furry friends. There are, however, a number of plants that are well-known for their toxicity. Dumbcane, oleander, and sago palm are three very pretty—but very poisonous—plants of note. Each of these plants can cause life-threatening reactions in dogs and cats.

Dumbcane has been known to cause the throat to swell, which can lead to suffocation. The plant oleander can seriously damage the heart, because it contains a chemical that is similar to digitalis. And the nuts of the sago palm plant can cause liver damage. Since all of these poisonous plants can be deadly to your pets, they should be banned in and around your home.

Five other fairly common plants are also important to note because of the health danger they can pose to dogs and cats. The beautiful holiday favorites poinsettias and mistletoe, along with philodendrons and dieffenbachias are well-known to cause gastrointestinal upset, sometimes severe, when eaten by dogs and cats. And for cats in particular, it is well documented that they can be poisoned by eating any part of any kind of lily. In the end, it’s best to keep all of these poisonous plants off your property to protect your pets.

A Primer on Poisonous Plants

According to The Humane Society of the United States, there are over 700 plants that have been identified as being poisonous to dogs and cats, which means these plants produce sufficient amounts of toxic substances to cause harmful effects in animals.

With so many indoor and outdoor plants capable of sickening your pets, there is no way to list them all here for your reference. The following list, however, includes a sampling of some of the most popular and frequently encountered plants that have been documented to cause adverse reactions in dogs and cats:

  • Aloe
  • Amaryllis
  • Asparagus fern
  • Azalea
  • Boston ivy
  • Caladium
  • Chrysanthemum
  • Daffodil
  • Delphinium
  • Dieffenbachias
  • Dumbcane
  • Elephant’s ear
  • English holly
  • Foxglove
  • Ivy
  • Jade plant
  • Jasmine
  • Japanese plum
  • Jerusalem cherry
  • Larkspur
  • Lilies
  • Mistletoe
  • Morning glory
  • Mums (pot and spider)
  • Oleander
  • Periwinkle
  • Philodendrons
  • Poinsettia
  • Privet
  • Sago palm
  • Tulips
  • Wisteria

For a much more extensive and searchable list of poisonous plants for dogs and cats (and horses!), go to the ASPCA’s “Toxic and Non-Toxic Plants List.” This list also provides pictures of the plants for easy identification and gives details on the type of adverse reactions each plant can cause in animals. The Humane Society of the United States website also has a listing of poisonous plants available in a PDF so that you can print it out.

Helping a Poisoned Pet

Since you can’t be with your pets all the time, you may not know if they’ve polished off a plant in secrecy. There is a wide range of symptoms that can alert you to the possibility of poisoning. These include:

  • Skin rash
  • Mouth irritation
  • Drooling
  • Vomiting
  • Diarrhea
  • Hallucinations
  • Seizures
  • Coma

Since poisoning symptoms can progress quickly and ultimately lead to death, contact your vet immediately if you suspect your pet has been poisoned. The ASPCA Animal Poison Control Center also has a 24-hour emergency poison hotline you can call if you have any questions (888-426-4435).

The Bottom Line on Pets & Plants

Just because something is “natural” doesn’t mean it is good for us—or our pets. While many plants contain medicinal and truly healing properties, others can induce life-threatening symptoms in dogs and cats when eaten in small or large quantities. It is up to us to keep our pets safe by making sure that the nature they encounter heals them and doesn’t harm them.


  • Why Do Dogs Eat Grass?” Accessed online May 16, 2018.
  • Toxic and Non-Toxic Plants List.” Accessed online May 16, 2018.
  • The Humane Society of the United States. “Plants Potentially Poisonous to Pets.” Accessed online May 19, 2018.
  • Hoffman, M. Vet On Call: The Best Home Remedies for Keeping Your Dog Healthy. Rodale Press, Inc., Emmaus, PA. 1999. p. 90.
  • Carlson, D. and Giffin, J. Dog Owners Home Veterinary Handbook. Howell Book House, New York. 1992. pp. 13-15.
  • Hoffman, M. Prevention’s Symptom Solver for Dogs & Cats. Rodale Press, Inc., Emmaus, PA. 1999. pp. 3 & 43.

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