Cats & Dogs
Potentially toxicConsulted 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
Pet safety reference
Water Hemlock
Cicuta species
Cowbane is a highly poisonous genus of plants in the carrot family, known for containing potent neurotoxins that affect the central nervous system. It is considered one of the most lethal plants in North America and should be strictly avoided in any environment accessible to pets.
CicutaCicuta speciesPoison ParsnipWater Hemlock
- Light
- Full sun to partial shade
- Habit
- Herbaceous perennial
- Care
- High (due to extreme toxicity)
Safety status
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
Excessive salivation, muscle tremors, seizures, rapid heart rate, and respiratory distress.
Escalation note
Extremely severe; ingestion of even small amounts can be fatal. Seek immediate emergency veterinary care if ingestion is suspected.
Dogs — concern notes
Common signs
Vomiting, violent seizures, muscle twitching, dilated pupils, and potential collapse.
Escalation note
Extremely severe; the toxins act rapidly on the nervous system. Contact a veterinarian or emergency animal poison control center immediately.
Safer alternatives
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Source evidence
ASPCA Toxic Plant List
toxicology · 99% reliability
Water Hemlock is listed as toxic to both cats and dogs, containing cicutoxin which causes severe neurotoxic effects.
NC State Extension Plant Toolbox
botanical · 94% reliability
Cicuta maculata is highly poisonous to humans and animals; all parts of the plant are toxic.
Questions about Water Hemlock
Is Water Hemlock toxic to cats?
Yes, Water Hemlock (Cicuta species) is extremely toxic to cats. It contains potent neurotoxins and is considered one of the most lethal plants in North America — even small amounts can be fatal.
What are the symptoms of Water Hemlock poisoning in cats?
Signs include excessive salivation, muscle tremors, seizures, rapid heart rate, and respiratory distress. Early warning signs can be drooling and weakness, but progression to severe neurological symptoms like seizures can happen very rapidly.
What should I do if my cat ate Water Hemlock?
Treat it as an immediate emergency — do not wait for symptoms to appear. Call your vet or the ASPCA Animal Poison Control Center at (888) 426-4435 right away. Severe signs can develop quickly and this plant can be fatal even in small quantities.
How quickly does Water Hemlock affect cats?
Onset can be very rapid, though the ASPCA listing does not specify an exact dose-to-onset timeline for cats. Because of the extreme severity and speed of potential progression — including seizures, respiratory depression, and death — any suspected ingestion must be treated as an immediate emergency without waiting to see if symptoms develop.
Is water hemlock poisonous to dogs?
Yes, water hemlock (Cicuta species) is extremely poisonous to dogs and is considered one of the most lethal plants in North America. It contains potent neurotoxins that act rapidly on the central nervous system, and even small amounts can be fatal.
What are the symptoms of water hemlock poisoning in dogs?
Symptoms include drooling, dilated pupils, weakness, agitation, muscle twitching, violent seizures, difficulty breathing, and cardiac abnormalities. Vomiting, diarrhea, extreme stomach pain, fever, and bloat have also been reported. Death from respiratory paralysis is possible.
What should I do if my dog ate water hemlock?
Call your vet or the ASPCA Animal Poison Control Center (888-426-4435) immediately — do not wait for symptoms to appear. The Pet Poison Helpline (855-764-7661) is also available 24/7. The time between symptom onset and severe poisoning can be very short, and prompt aggressive treatment including seizure control and supportive care offers the only realistic chance of survival.
How quickly does water hemlock affect dogs after ingestion?
The toxins act rapidly on the nervous system, though precise dose-to-onset times are not published in the cited sources. Because the window between early symptoms and severe poisoning is very short, the Pet Poison Helpline stresses that immediate treatment is critical — any suspected ingestion should be treated as an emergency without waiting to see how symptoms develop.
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