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
Cow Parsnip
Heracleum maximum
Cow parsnip is a large, herbaceous perennial member of the carrot family known for its tall stature and umbrella-like flower clusters. It contains furanocoumarins that can cause significant skin and mucosal irritation upon contact.
American cow parsnipCow parsnipHeracleum lanatumHeracleum maximum
- Light
- Partial shade to full sun
- Habit
- Herbaceous perennial
- Care
- Low
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
Dermatitis, blistering, redness, and irritation of the mouth or throat if ingested.
Escalation note
The plant contains photosensitizing compounds that can cause severe skin reactions when exposed to sunlight. Please contact your veterinarian if you suspect ingestion or skin contact.
Dogs — concern notes
Common signs
Skin inflammation, blistering, oral irritation, and potential gastrointestinal upset.
Escalation note
Contact with the sap can lead to phytophotodermatitis, where skin becomes hypersensitive to UV light. Seek veterinary care if your pet shows signs of distress or skin lesions.
Safer alternatives
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Source evidence
ASPCA Toxic Plant List
toxicology · 99% reliability
Cow parsnip is listed as toxic to both cats and dogs due to its potential for causing dermatitis and irritation.
NC State Extension Plant Toolbox
botanical · 94% reliability
Heracleum maximum is a native perennial that can cause skin irritation in humans and animals due to furanocoumarins.
Questions about Cow Parsnip
Is cow parsnip toxic to cats?
Yes, cow parsnip (Heracleum maximum) is considered potentially toxic to cats. It contains furanocoumarins — photosensitizing compounds — that cause dermatitis, blistering, redness, and irritation of the mouth or throat on contact or ingestion.
What are the symptoms if a cat touches or eats cow parsnip?
If a cat chews the leaves, expect mouth and tongue irritation and possible drooling. Sap on the skin — most often on the muzzle, paws, or ears — causes redness, blistering, and hair loss once that area is exposed to sunlight, typically within 24–48 hours. You may also see the cat pawing at its face or squinting from eye irritation.
What should I do if my cat got into cow parsnip?
Move the cat indoors and away from direct sunlight immediately. Wearing gloves, wipe any sap off the fur with a damp cloth and rinse the mouth gently with cool water if the cat will tolerate it — do not induce vomiting. Then call your vet or the ASPCA Animal Poison Control Center at (888) 426-4435.
How long do cow parsnip reactions last in cats?
Oral irritation typically settles within a day once the cat stops chewing. Skin reactions are slower — they appear after the affected area meets UV light and can take days to a week or more to fully resolve. Because cats are small and sun exposure can rapidly worsen blistering, don't wait to see if symptoms improve on their own.
Is cow parsnip toxic to dogs?
Yes, cow parsnip (Heracleum maximum) is potentially toxic to dogs. Its sap contains furanocoumarins that cause skin inflammation, blistering, and oral irritation, and can lead to gastrointestinal upset if ingested.
What does cow parsnip poisoning look like on a dog's skin?
Skin reactions appear as redness, blistering, or peeling on areas the sap contacted — commonly the muzzle, lips, belly, and paws. The reaction is driven by phytophotodermatitis: the sap makes skin hypersensitive to UV light, so symptoms develop over 24–48 hours after sun exposure and can take 1–2 weeks to fully heal. Reactions are significantly worse if the dog goes outside in sunlight after contact.
What should I do if my dog touched or chewed cow parsnip?
Bring your dog inside immediately and keep them away from sunlight. Wearing gloves, wash all contact areas thoroughly with soap and cool water, and rinse the mouth if the dog chewed any leaves. Do not induce vomiting. Call your vet or the ASPCA Animal Poison Control Center at (888) 426-4435.
When is cow parsnip exposure in dogs an emergency?
Call your vet promptly — don't wait it out — if you see blistering or open skin lesions, swelling around the mouth, persistent drooling, or refusal to eat. Severe phytophotodermatitis can ulcerate and become infected; early treatment reduces the risk of serious skin damage.
Same safety verdict
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