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ToxicEmergency

Is water hemlock toxic to dogs? Yes: extremely toxic

Extremely toxic. Water hemlock, one of North America's most toxic plants, causes rapid seizures and breathing failure, even in small amounts.

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, Canada, Australia, New Zealand, Belgium, France, JM, PR, Singapore, Switzerland, TT, VI

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.

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.

Australia

Animal Poisons Helpline1300 869 73824/7 · From A$79 per consultation; their website has the current price · Staffed by poisons information consultants with emergency vet or pharmacy backgrounds.

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.

Belgium

Centre Antipoisons / Antigifcentrum070 245 245Animal questions: weekdays 8:00 to 16:00; weekends and public holidays 10:00 to 16:00 · Free call · Human poison center that also takes animal questions; human emergencies get priority, so call your vet first.

France

CNITV (Centre National d'Informations Toxicologiques Vétérinaires)+33 4 78 87 10 408:30 am to midnight, every day · Veterinary poison center that answers vets and pet owners; call your own vet first if you can.

JM

Pet Poison Helpline+1 (952) 853-171624/7 · A fee applies; their website has the current price · Serves the US, Canada and the Caribbean. This is the number it gives for other Caribbean islands; it also lists a toll-free number for the Caribbean, +1 (877) 416-7319.

PR

Pet Poison Helpline+1 (877) 416-731924/7 · A fee applies; their website has the current price · Serves the US, Canada and the Caribbean; this is its toll-free number for callers in the Caribbean and the US Virgin Islands.

Singapore

Animal Poisons Helpline+65 3106 421624/7 · Ask about the fee when you call · Australia-based animal poison service; this is the Singapore number listed on its site.

Switzerland

Tox Info Suisse14524/7 · Swiss poison center that also tells owners how risky an animal exposure is; from abroad call +41 44 251 51 51.

TT

Pet Poison Helpline+1 (952) 853-171624/7 · A fee applies; their website has the current price · Serves the US, Canada and the Caribbean. This is the number it gives for other Caribbean islands; it also lists a toll-free number for the Caribbean, +1 (877) 416-7319.

VI

Pet Poison Helpline+1 (877) 416-731924/7 · A fee applies; their website has the current price · Serves the US, Canada and the Caribbean; this is its toll-free number for callers in the Caribbean and the US Virgin Islands.

Find an emergency vet

Water hemlock and dogs: key facts

Verdict: Toxic · Emergency: get help now
What it can do: Severe stomach pain, diarrhea, tremors, seizures and dilated pupils. All 8
How fast: Rapid
What to do now: Call your vet or a pet poison line now. All steps
Sources: ASPCA Animal Poison Control, Pet Poison Helpline. Reviewed 9 October 2026.

What should I do if my dog ate water hemlock?

Call your vet or a pet poison line now.
Head to an emergency vet right away, even if your dog seems fine.
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.

Symptoms to watch for

Severe stomach pain
Diarrhea
Tremors
Seizures
Dilated pupils
Fever
Slowed breathing
Abnormal heart rhythm

When signs appear: Rapid

Why

It contains cicutoxin, a poison that causes seizures. The roots hold the most toxin.

Sources

Guide reviewed 9 October 2026. Page updated 7 November 2026.

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