Is Cow parsnip Toxic to Dogs and Cats? (2026)
Heracleum maximum
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Quick facts
| Toxic to dogs | Yes |
|---|---|
| Toxic to cats | Yes |
| Toxic to horses | Yes |
| Toxic component | Furocoumarins (cause skin photosensitization on contact with sap plus sunlight) |
| Onset of symptoms | Skin reaction over 24-48 hours after sap contact plus sunlight |
| Indoor / outdoor | outdoor |
If your pet ate this plant
Both lines are staffed 24/7. A consultation fee applies to each. Do not wait for symptoms to appear before calling.
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Symptoms in dogs
- Skin burns/blistering after sap contact and sun exposure
- Vomiting if eaten
Symptoms in cats
- Skin burns/blistering after sap contact and sun exposure
- Vomiting if eaten
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What to do
Keep the pet out of sunlight and wash any sap-contacted skin with soap and water; this plant is dangerous primarily through skin contact plus sunlight, not ingestion alone.
Toxic component and mechanism
The toxic component in Cow parsnip is furocoumarins (cause skin photosensitization on contact with sap plus sunlight).
What makes this plant different
Cow Parsnip is a native look-alike for the more infamous invasive Giant Hogweed, and shares the same phytophotodermatitis risk — sap contact followed by sunlight exposure, not ingestion, is the primary danger with both plants.
Plant identification
- Scientific name
- Heracleum maximum
- Family
- Apiaceae
- Also known as
- Cow parsnip, Giant Hogweed
- Typically found
- outdoor
Pet-safe alternatives
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Related plants
Bishop's Weed
Ammi majus
Cilantro
Coriandrum sativum
Cowbane
Cicuta species
Dill
Anethum graveolena
Giant Hogweed
Heracleum maximum
Last verified: July 2, 2026 · Cross-referenced with ASPCA Animal Poison Control