What should I do if my cat ate Poison Hemlock?

Call immediately. Any suspected ingestion of poison hemlock by a cat is an emergency — contact your nearest emergency veterinary clinic right away, and call ASPCA Animal Poison Control at (888) 426-4435 en route. Bring a piece of the plant if you can do so safely.

What should I do if my dog ate Poison Hemlock?

Call immediately. Any amount of poison hemlock in a dog is a veterinary emergency — head to the nearest emergency clinic and call ASPCA Animal Poison Control at (888) 426-4435 on the way. Don’t wait for severe signs; the alkaloids can progress to respiratory failure quickly.

Poison Hemlock — (c) L.J. Lamera, some rights reserved (CC BY), uploaded by L.J. Lamera — Photo by (c) L.J. Lamera, some rights reserved (CC BY), uploaded by L.J. LameraiNaturalistCC BY

Photo by (c) L.J. Lamera, some rights reserved (CC BY), uploaded by L.J. LameraiNaturalistCC BY

Pet safety reference

Poison Hemlock

Q: Is Poison Hemlock safe for cats?

Poison Hemlock is potentially toxic to cats. This plant is extremely toxic; ingestion of even small amounts can be fatal. Seek immediate veterinary emergency care if ingestion is suspected.

Q: Is Poison Hemlock safe for dogs?

Poison Hemlock is potentially toxic to dogs. The toxins in this plant act rapidly on the nervous system. Contact a veterinarian or animal poison control center immediately if your dog consumes any part of this plant.

Conium maculatum

Poison Hemlock is a highly dangerous biennial herb containing potent piperidine alkaloids that affect the nervous system. It is considered one of the most toxic plants and should be strictly avoided in any environment accessible to pets.

Check a list

Conium maculatumDeadly HemlockPoison Hemlock

Light: Full sun to partial shade
Habit: Herbaceous biennial
Care: High (invasive weed)

Safety status

Cats & Dogs

Potentially toxic

Consulted references classify the plant as toxic or irritating for that pet type.

Verified against ASPCA/provenance audit 2026-05-06 on May 6, 2026.

Sources

ASPCA Toxic Plant List

If a pet has chewed or swallowed plant material and is showing symptoms, contact a veterinarian or poison resource immediately. This product is for structured reference, not diagnosis.

Cats — concern notes

Common signs

Tremors, salivation, dilated pupils, respiratory distress, and potential paralysis.

Escalation note

This plant is extremely toxic; ingestion of even small amounts can be fatal. Seek immediate veterinary emergency care if ingestion is suspected.

Dogs — concern notes

Common signs

Muscle weakness, incoordination, rapid heart rate, seizures, and respiratory failure.

Escalation note

The toxins in this plant act rapidly on the nervous system. Contact a veterinarian or animal poison control center immediately if your dog consumes any part of this plant.

Safer alternatives

No hand-picked alternatives for this plant yet. You can still pick your own using the Compare button on any other plant.

Source evidence

ASPCA Toxic Plant List

toxicology · 99% reliability

Open source

Poison Hemlock is listed as toxic to both cats and dogs due to the presence of coniine and related alkaloids.

NC State Extension Plant Toolbox

botanical · 94% reliability

Open source

Conium maculatum is a highly poisonous plant that is toxic to humans and animals if ingested.

cats safety page My cat ate Poison Hemlock dogs safety page My dog ate Poison Hemlock

Same safety verdict

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Potentially toxic for cats & dogs.

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