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Toxic

Is hydrangea toxic to dogs?

Toxic. Hydrangea can cause vomiting, diarrhea and low energy; serious cyanide poisoning is rare.

If your dog ate or touched this, call your vet or a pet poison line now

United States

ASPCA Poison Control+1 (888) 426-443524/7, 365 days a year · A consultation fee may apply · Run by the ASPCA for pet owners and vets.
Pet Poison Helpline+1 (855) 764-766124/7 · A fee applies; their website has the current price · Serves the US, Canada and the Caribbean.

Poison lines in other countries: United Kingdom, Australia, Canada, New Zealand

United Kingdom

Animal PoisonLine+44 1202 50900024 hours a day · A fee applies; their website has the current price · Run by the Veterinary Poisons Information Service for pet owners; for collapse, fits or breathing trouble, call your vet.

Australia

Animal Poisons Helpline1300 869 73824/7 · From A$75 per consultation; their website has the current price · Staffed by poisons information consultants with emergency vet or pharmacy backgrounds.

Canada

Pet Poison Helpline+1 (855) 764-766124/7 · A fee applies; their website has the current price · Serves the US, Canada and the Caribbean.

New Zealand

NZ Animal Poisons Helpline0800 869 73824/7 · Charges apply · The NZ National Poisons Centre does not advise on animals and refers pet owners here.

Find an emergency vet

What to do now

Call your vet or a pet poison line now.
Take any plant pieces away and rinse your dog's mouth with water.
Bring a piece of the plant in a bag, or a photo, to help identify it.

Don't

Don't make your dog vomit unless a vet tells you to.
Don't give milk, oil, salt or other home remedies unless a vet tells you to.

Signs to watch for

Vomiting
Diarrhea
Low energy (depression)

Why

Hydrangeas contain a cyanogenic glycoside, a substance that can release cyanide, but it usually causes only stomach upset.

Sources

Guide reviewed 9 October 2026.

General information from the sources above, not a diagnosis. When in doubt, call your vet.