Toxicity level
MildModerateSevere
- Contains cyanide-like compounds
- Within hours
- Affects: Gut
Did you know? Large amounts can cause cyanide-type effects, but usually just GI upset.
Verdict
Feed only in moderation
Key concern
Cyanogenic glycoside
Species
🐱 Cats
Why this verdict for cats
Hydrangea can cause vomiting and diarrhea in cats; serious poisoning needs a large amount, but it is best kept away.
Warning signs to watch for
- Vomiting
- Diarrhea
🍽️ Feeding it safely?
Frequently asked questions
Can cats eat hydrangea?
In moderation. Hydrangea can cause vomiting and diarrhea in cats; serious poisoning needs a large amount, but it is best kept away.
How much hydrangea can cats have?
None — hydrangea is not safe for cats and should be avoided entirely. When in doubt, ask your vet.
Is hydrangea safe for dogs too?
Verdicts can differ between species. See the dog answer for hydrangea →
More plants for cats
By the CanMyPet Editorial Team · Reviewed against ASPCA Animal Poison Control, the American Kennel Club (AKC) and Pet Poison Helpline · Last updated June 22, 2026.
Sources
- ASPCA — People Foods to Avoid Feeding Your Pets
- American Kennel Club — Dog Nutrition
- Pet Poison Helpline — Poison List
CanMyPet provides general information reviewed against trusted sources (ASPCA, AKC, Pet Poison Helpline). It is not a substitute for professional veterinary advice. When in doubt, always contact your veterinarian.