Plants toxic to dogs

The facts in one table

Sources: ASPCA Animal Poison Control Center · ASPCA Animal Poison Control Center · ASPCA · ASPCA Animal Poison Control Center · ASPCA

Sago palm: the one that kills dogs

The sago palm, Cycas revoluta, is a cycad rather than a true palm, and it is sold as an ornamental in warm regions and as a houseplant elsewhere. The ASPCA describes vomiting as very common after exposure, developing within minutes of ingestion, with liver failure potentially developing within three days. Its own figure — up to half of ingestion cases fatal — is the starkest number on any of these pages, and survival chances improve with early intervention, which is the whole argument for calling immediately rather than waiting.

Concentration matters here. The seeds hold the highest level of toxin and as few as one or two can be fatal, which turns a dropped seed on a patio into a genuine emergency for a dog that investigates with its mouth. For a household with a dog, the only reliable approach is not to have the plant.

If your animal has eaten part of a plant, do not wait for symptoms and do not try to treat it at home: consult a veterinarian straight away, or call the ASPCA Animal Poison Control Center on (888) 426-4435 or the Pet Poison Helpline on (855) 764-7661.

Sources: ASPCA Animal Poison Control Center · ASPCA

Oleander and lily of the valley: cardiac plants

Oleander, Nerium oleander, is listed by the ASPCA as toxic to dogs, cats and horses, with cardiac glycosides as its toxic principle and effects including drooling, abdominal pain, diarrhoea, colic, depression and death. It is a common hedging and roadside plant in Mediterranean and subtropical climates, which is exactly where a dog is most likely to meet it.

Lily of the valley, Convallaria majalis, works on the same system through cardenolides including convallarin, with the ASPCA listing vomiting, irregular heartbeat, low blood pressure, disorientation, coma and seizures. Both are plants where the problem is not a sore mouth but a heart rhythm, and both belong in the same category as the sago palm for urgency.

Sources: ASPCA Animal Poison Control Center · ASPCA Animal Poison Control Center

The garden and houseplant tier

Azalea and rhododendron come next, with grayanotoxin as the toxic principle and effects the ASPCA lists as vomiting, diarrhoea, weakness and cardiac failure. Tulips follow, with tulipalin A and B: the ASPCA notes that tulips and tulip bulbs can cause significant stomach upset, depression and possible intestinal obstruction if large bulbs are swallowed — which makes a dog that digs up a newly planted bed a specific risk in autumn.

At the bottom sit aloe vera, with saponins and anthraquinones causing vomiting, lethargy, diarrhoea and in some cases red-coloured urine, and the calcium-oxalate houseplants — monstera, pothos and dieffenbachia — whose effect is painful mouth irritation rather than systemic illness. Lower severity still means a phone call; it does not mean nothing happened.

Sources: ASPCA Animal Poison Control Center · ASPCA Animal Poison Control Center · ASPCA Animal Poison Control Center · Pet Poison Helpline · ASPCA Animal Poison Control Center

What to do

Call first, and bring the plant. Identification is what determines whether this is a sore mouth or a liver emergency, and a photo of the leaf and the whole plant is more use than a description. Do not try anything at home: with the sago palm the ASPCA's own point is that early veterinary intervention improves survival, and time spent on home remedies is time taken from that.

• ASPCA Animal Poison Control Center: (888) 426-4435
• Pet Poison Helpline: (855) 764-7661

If your animal has eaten part of a plant, do not wait for symptoms and do not try to treat it at home: consult a veterinarian straight away, or call the ASPCA Animal Poison Control Center on (888) 426-4435 or the Pet Poison Helpline on (855) 764-7661.

Sources: ASPCA Animal Poison Control Center · ASPCA

What most people get wrong

• "A sago palm is just a palm." It is a cycad, and the ASPCA reports up to 50% of ingestion cases as fatal, with one or two seeds potentially enough.
• "If the dog seems fine, it is fine." With the sago palm, liver failure can develop within three days of an ingestion that looked minor.
• "Only the bulb of a tulip matters." The ASPCA lists tulips and tulip bulbs together; large bulbs also raise the risk of intestinal obstruction.
• "Aloe vera is medicinal, so it is safe." The ASPCA lists saponins and anthraquinones as its toxic principles for dogs and cats.

Sources: ASPCA Animal Poison Control Center · ASPCA Animal Poison Control Center · ASPCA Animal Poison Control Center

Frequently asked questions

What is the most dangerous plant for dogs?

The sago palm. The ASPCA reports up to 50% of ingestion cases as fatal, with the seeds the most toxic part and as few as one or two potentially enough.

Are tulips toxic to dogs?

Yes. The ASPCA gives tulipalin A and B as the toxic principles and lists significant stomach upset, depression and possible intestinal obstruction if large bulbs are swallowed.

What should I do if my dog ate a toxic plant?

Call your veterinarian or a poison control centre immediately — the ASPCA Animal Poison Control Center on (888) 426-4435 or the Pet Poison Helpline on (855) 764-7661 — and take the plant or a photo with you.