Many of the most popular indoor plants are toxic to dogs, including pothos, philodendron, sago palm, aloe vera, and dieffenbachia. Some cause mild stomach upset, while others can lead to organ failure and death. Knowing which plants pose a real threat helps you decide what to keep, what to move out of reach, and what to replace entirely.
The Most Dangerous Indoor Plants
A handful of common houseplants can cause life-threatening damage, not just an upset stomach. These are the ones to take most seriously.
Sago palm: This is arguably the most dangerous houseplant for dogs. Every part of the plant is toxic, but the seeds (sometimes called nuts) are the most concentrated source. The plant contains compounds that, once metabolized in the gut, cause severe liver damage and can also harm the nervous system. Retrospective veterinary studies have found survival rates of only 36 to 50% in dogs with confirmed sago palm poisoning. If your dog chews on any part of this plant, treat it as a true emergency.
Lily of the valley: This plant contains cardiac glycosides, compounds that directly interfere with heart rhythm. Ingestion causes vomiting, diarrhea, and an irregular heartbeat that can become dangerous without treatment.
Castor bean plant: Less common indoors but sometimes grown as a decorative houseplant, castor bean contains ricin in its seeds. Even small amounts can cause severe poisoning.
Oleander: Like lily of the valley, oleander contains cardiac glycosides. All parts of the plant are toxic, and even small ingestions can affect heart function.
Plants That Cause Painful Mouth Irritation
A large group of popular houseplants belong to the Araceae family and contain tiny, needle-shaped calcium oxalate crystals throughout their leaves and stems. When a dog chews on them, these microscopic crystals are released and physically puncture the soft tissues of the mouth, tongue, and throat. The result is immediate, intense pain and swelling.
Dogs that bite into these plants typically drop the piece quickly because of how much it hurts. That’s actually somewhat protective, since the pain limits how much they consume. You’ll see drooling, pawing at the mouth, a swollen tongue, and sometimes difficulty breathing if the throat swells. Vomiting and loss of appetite often follow.
Common houseplants in this category include:
- Dieffenbachia (dumb cane): One of the worst offenders. Contains both calcium oxalate crystals and additional toxic proteins that intensify the burning and inflammation.
- Philodendron: All species are toxic. In severe cases, ingestion has been linked to kidney problems.
- Pothos (golden pothos, devil’s ivy): One of the most common houseplants in the world, and one dogs frequently encounter.
- Peace lily: Despite the name, not a true lily. It causes oral pain and drooling but very rarely leads to serious or life-threatening problems.
- Caladium (angel wings): The colorful leaves are especially appealing to curious pets.
- Swiss cheese plant (monstera): Popular for its dramatic leaves, but the same crystal-based toxicity applies.
- Chinese evergreen: Another Araceae family member with the same mechanism.
- Calla lily: Not a true lily either, but contains the same irritating crystals.
- Elephant’s ear (alocasia): Large, eye-catching leaves that contain crystals throughout.
Plants That Cause Digestive and Organ Problems
Aloe vera: The gel inside aloe leaves is a home remedy staple for humans, but the plant contains saponins and compounds called anthraquinones that act as strong irritants in a dog’s digestive tract. Symptoms include vomiting, diarrhea, and lethargy.
Snake plant (sansevieria): Another extremely common houseplant. Ingestion typically causes drooling, vomiting, diarrhea, decreased appetite, and lethargy. It’s generally considered mild to moderate in severity.
Corn plant (dracaena): Several dracaena species are popular indoors, and all are toxic to dogs, causing vomiting (sometimes with blood), depression, and loss of appetite.
Asparagus fern: The berries are the most toxic part, causing vomiting and diarrhea. Repeated skin contact with the plant can also cause dermatitis.
Kalanchoe: Contains compounds that can affect the heart in large enough quantities. More commonly causes vomiting and diarrhea.
Cyclamen: The highest concentration of toxins is in the roots (tubers). Ingestion of the tuber can cause severe vomiting, and in large amounts, heart rhythm abnormalities and seizures.
English ivy: All parts are toxic, causing drooling, vomiting, diarrhea, and abdominal pain.
A Note About Lilies and Dogs
Lilies get a lot of attention as pet toxins, and rightly so, but the risk varies significantly between dogs and cats. True lilies (Asiatic lilies, Easter lilies) and daylilies cause severe, often fatal kidney failure in cats. They’re toxic to dogs too, but the effects are much less severe. The real danger of keeping these lilies indoors is if you also have cats in the home.
That said, lily of the valley is a genuine cardiac threat to dogs. And peace lilies, while they share the name, work through a completely different mechanism (calcium oxalate crystals) and rarely cause serious harm. The word “lily” covers a wide range of plants with very different risk profiles, so it’s worth knowing exactly which type you have.
What to Do if Your Dog Eats a Toxic Plant
If you see your dog chewing on a plant you suspect is toxic, try to identify the plant and then call your veterinarian or an emergency veterinary clinic immediately. Be ready to tell them what the plant is, how much your dog may have eaten, when it happened, and your dog’s approximate weight. If you can, bring a piece of the plant or take a photo.
If you can’t reach a vet right away, two 24/7 poison hotlines can help: the ASPCA Animal Poison Control Center at (888) 426-4435 and the Pet Poison Helpline at 855-764-7661. Both may charge a consultation fee. These services can walk you through first aid steps, tell you whether it’s appropriate to induce vomiting at home, and help you gauge how urgently your dog needs professional care.
Do not try to induce vomiting on your own without professional guidance. For plants that cause mouth irritation (the calcium oxalate group), vomiting would force those crystals back through the throat a second time, making things worse.
Safe Indoor Plants for Dog Owners
If you want greenery without worry, plenty of popular houseplants are completely nontoxic to dogs. Spider plants are hardy, easy to grow, and safe. Boston ferns, African violets, and phalaenopsis orchids (moth orchids) are all confirmed nontoxic. Christmas cactus, cast iron plants, and baby rubber plants round out a solid list of dog-friendly options.
The ASPCA maintains a searchable database of toxic and nontoxic plants at aspca.org. Before you bring any new plant home, a quick search there takes seconds and can save you a lot of trouble. When in doubt about a plant you already own, moving it to a high shelf or hanging planter your dog can’t reach is a reasonable compromise, though removing the plant entirely is the only way to eliminate the risk completely.