Is Giant Hogweed 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 severe 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
- Severe skin burns/blistering after sap contact and sun exposure
- Vomiting if eaten
Symptoms in cats
- Severe 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 immediately with soap and water; contact a vet for significant burns or if the plant was eaten. This plant is dangerous primarily through skin contact plus sunlight (phytophotodermatitis), not ingestion alone.
Toxic component and mechanism
The toxic component in Giant Hogweed is furocoumarins (cause severe skin photosensitization on contact with sap plus sunlight).
What makes this plant different
Giant Hogweed is dangerous primarily through skin contact rather than ingestion — its sap causes severe burns and blistering when combined with sunlight exposure (phytophotodermatitis), a fundamentally different risk pathway from the GI-focused toxicity of most plants on this list.
Plant identification
- Scientific name
- Heracleum maximum
- Family
- Apiaceae
- Also known as
- Giant Hogweed, Cow Parsnip
- Typically found
- outdoor
Pet-safe alternatives
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Last verified: July 2, 2026 · Cross-referenced with ASPCA Animal Poison Control