20 Plants That Are Harmful to Dogs

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Dogs have a habit of sampling just about anything in their environment, and that includes household and garden plants. Many popular ornamentals actually contain toxic compounds that can trigger anything from mild stomach upset to, honestly, life-threatening organ damage.

Knowing which plants are risky for your dog helps you make smarter choices about what grows around your home. This guide runs through twenty plants that can be harmful to dogs, from classic favorites like azaleas and tulips to the ever-present snake plant. For each one, you’ll find out what makes it dangerous and why it’s better to keep these out of paw’s reach.

1) Azalea

Azaleas are seriously toxic to dogs, as compounds called grayanotoxins are found throughout the plant, not just the pretty flowers. Leaves, flowers, seeds: all a bad idea.

Even a small nibble can do real harm. Just two ounces can be enough to make a 60-pound dog very sick; the toxic dose is surprisingly low.

Symptoms can show up anywhere from 20 minutes to a couple of hours after eating. Look for vomiting, diarrhea, drooling, weakness, or tremors. 

2) Sago Palm

Sago palms are among the most toxic houseplants you’ll find, and they’re popular in landscaping too. Every part is poisonous, including seeds, leaves, and roots. The toxins can cause awful stomach upset and even liver failure in dogs.

Symptoms might hit in as little as 15 minutes, or take a few hours. Vomiting, lethargy, and stomach pain are the usual early signs. If your dog chews on a sago palm, don’t wait, get to the vet right away.

3) Oleander

Oleander is notoriously dangerous for dogs. Every single part, flowers, leaves, stems, is toxic.

This plant contains cardiac glycosides that mess with your dog’s heart, affecting how their cells handle electrolytes. If your dog nibbles oleander, you might see vomiting, diarrhea, drooling, or a weird heartbeat. 

4) Tulip

Tulips have toxins called tulipalin A and B. The bulbs are the worst, but even the stems and flowers aren’t safe.

If your dog eats tulips, you might notice vomiting, diarrhea, drooling, or belly pain. Suspect tulip poisoning? Get your pup checked out as soon as possible.

5) Autumn Crocus

Autumn crocus is packed with colchicine, a compound that’s bad news for dogs. Every part, including flowers, leaves, bulbs, is risky.

Eaten in any amount, it can cause severe vomiting, GI bleeding, and even kidney or liver damage. In the worst cases, it can affect breathing. It doesn’t take much to cause a big problem.

6) Cyclamen

Cyclamen contains triterpenoid saponins, which are pretty nasty for dogs. The tubers (those underground parts) are especially toxic, but the whole plant is a hazard.

Typical symptoms: vomiting, diarrhea, drooling, and general stomach upset. Sometimes, it gets more serious; think heart problems, seizures, or trouble breathing.

Smaller dogs are at higher risk, just because of their size. If you suspect cyclamen poisoning, get help fast.

7) Foxglove

Foxglove is beautiful but dangerous. It contains digoxin, a compound that directly affects the heart. All parts of this plant are off-limits.

Foxglove poisoning can show up as vomiting, diarrhea, weakness, and strange heart rhythms. In bad cases, it can be fatal.

If your dog might have eaten foxglove, don’t wait, contact your vet. Honestly, it’s best to just keep these out of your yard altogether.

8) Kalanchoe

Kalanchoe is a popular, colorful houseplant, but it’s got bufadienolides – cardiac toxins that can mess with your dog’s heart and digestion.

Common symptoms are vomiting and diarrhea. Rarely, it can also cause abnormal heart rhythms. The flowers are especially dangerous.

9) Rhododendron

Rhododendrons are another plant loaded with grayanotoxins. Every part is toxic and can mess with your dog’s heart and nervous system.

Signs include vomiting, diarrhea, drooling, and weakness. If it’s a bad case, you could see irregular heartbeats, paralysis, even death. Even a little bit can be enough to cause trouble, so don’t hesitate to get to the vet if you suspect exposure.

10) Yew

Yew plants are extremely toxic. Leaves, seeds, bark, it’s all bad for dogs.

Symptoms can show up quickly, sometimes in just an hour or two. Look for vomiting, diarrhea, trouble breathing, and heart problems. Yew poisoning can cause cardiac arrest.

Honestly, it’s safest to keep yew far away from where your dog can roam.

11) Chrysanthemum

Chrysanthemums are toxic to dogs. The whole plant contains nasty stuff like pyrethrins and sesquiterpene lactones.

If your dog eats any part, you might notice vomiting, diarrhea, drooling, or even skin irritation. Sometimes, tremors crop up too.

12) Daffodil

Daffodils have lycorine, a toxic alkaloid that causes vomiting and GI issues. The bulbs are especially concentrated with toxins, but the whole plant is risky.

If your dog chews on daffodils, you might see vomiting, diarrhea, drooling, or belly pain. Best to plant them somewhere your dog can’t get to.

13) Dieffenbachia (Dumb Cane)

Dieffenbachia, or Dumb Cane, is toxic to dogs thanks to insoluble calcium oxalate crystals in its stems and leaves. If your dog chews on it, those needle-like crystals cause instant pain and swelling.

Watch for drooling, trouble swallowing, vomiting, or swelling in the mouth. In serious cases, breathing can get tough. 

14) English Ivy

English ivy is another sneaky one, as its toxins can make your dog really sick, even in small amounts. Expect vomiting, diarrhea, drooling, or belly pain.

In worse cases, you could see swelling in the mouth and throat or even trouble breathing. Keep this plant far out of reach, whether it’s in your yard or inside.

If your dog eats English ivy, don’t hesitate, contact your vet for advice.

15) Lily of the Valley

Lily of the Valley is loaded with cardiac glycosides and saponins; both bad for your dog’s heart and gut. Every part is highly toxic, even the water from its vase.

If your dog gets into it, you might see vomiting, diarrhea, irregular heartbeats, or even seizures. 

16) Castor Bean Plant

Castor bean plants contain ricin, which is incredibly dangerous. Even a small amount can be deadly, especially the seeds.

Symptoms include vomiting, diarrhea, belly pain, and lethargy. In severe cases, kidney failure or convulsions can follow.

They pop up in California landscapes and along trails, so keep your dog leashed on walks to avoid any accidents.

17) Amaryllis

Amaryllis is toxic to dogs, mostly due to lycorine. All parts are harmful, but the bulbs are the worst offenders.

If your dog eats amaryllis, watch for vomiting, diarrhea, drooling, and abdominal pain. More severe cases might bring tremors, lethargy, or blood pressure changes.

It’s a popular holiday plant, so keep it well out of reach.

18) Hydrangea

Hydrangeas are gorgeous garden shrubs, but every part (flowers, leaves, stems, buds) is toxic to dogs.

Signs of hydrangea poisoning include vomiting, diarrhea, and lethargy. If you think your dog took a bite, call your vet or the Pet Poison Helpline right away.

19) Sansevieria (Snake Plant)

Snake plants have saponins, which help protect them from pests but can make your dog sick. If your pup chews the leaves, expect nausea, vomiting, and diarrhea.

The bitter taste usually keeps dogs from eating much, but some still try. Even a small bite can cause mouth irritation and digestive upset.

20) Philodendron

Philodendrons have these pesky insoluble calcium oxalate crystals that are toxic to dogs. If your pup chews or swallows any part of the plant, those sharp crystals can cause instant irritation within the mouth, throat, even the digestive tract. 

Even a small nibble might set off drooling, oral pain, vomiting, or trouble swallowing. If you notice any of that, it’s best to reach out to your vet or the Pet Poison Helpline.

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Jessica L.
About the author

Jessica L.

Jessica is a dedicated horticulturist with a deep passion for gardening, landscaping, and supporting local wildlife. She combines her expertise in plant care with a love for creating vibrant, sustainable outdoor spaces that nurture biodiversity.

Read more about Pond Informer.

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