Is hydrangea toxic to dogs or cats?
Cyanogenic compounds in theory; stomach upset in practice.
Same mild GI risk for cats.
Hydrangeas technically contain cyanogenic glycosides, but real-world cases almost always amount to vomiting and diarrhea from chewing leaves or flowers. Massive ingestion would be needed for worse. Watch, hydrate, and call if signs persist.
Signs to watch for
- Vomiting
- Diarrhea
- Lethargy
Sources: ASPCA toxic and non-toxic plant list, Pet Poison Helpline. Verdicts are conservative by design: where evidence is thin we choose the stricter rating.
This is general educational information, not veterinary advice. When in doubt about your own pet, ask your veterinarian.
If your pet just ate something risky, act now: call your vet, ASPCA Animal Poison Control at (888) 426-4435, or Pet Poison Helpline at (855) 764-7661 (consultation fees may apply).