Hydrangea: is it toxic to cats and dogs?

Pet safety summary

ASPCA lists Hydrangea arborescens as toxic to cats and dogs. The source identifies cyanogenic glycoside and notes that gastrointestinal disturbance is more typical than cyanide intoxication.

Hydrangea is a broad common name. This page is scoped to the ASPCA entry for Hydrangea arborescens rather than assuming every Hydrangea species has an identical toxicity profile.

Cats

Cat conclusion: ASPCA Animal Poison Control identifies Hydrangea as toxic to cats. Keep the plant out of reach and contact a veterinarian or poison-control service if exposure is suspected.

Dogs

Dog conclusion: ASPCA Animal Poison Control identifies Hydrangea as toxic to dogs. Keep the plant out of reach and contact a veterinarian or poison-control service if exposure is suspected.

Clinical signs reported by the source

• vomiting
• depression
• diarrhea

What to do if your pet ate it

Remove access to the plant. Save the plant label or a clear photo, note the part and approximate amount eaten, and contact your veterinarian or a poison-control service when the source identifies a toxicity risk. Do not induce vomiting unless a veterinary professional specifically tells you to.

Evidence and identity

Scientific name used on this page: Hydrangea arborescens

Source scientific name: Hydrangea arborescens

Source notes: Cyanogenic glycoside

Source

ASPCA Animal Poison Control plant safety entry for Hydrangea

Source reviewed for Batch 30 on August 3, 2026.

Emergency contacts

ASPCA Animal Poison Control: (888) 426-4435

Pet Poison Helpline: (855) 764-7661

If your pet is having trouble breathing, collapsing, having seizures, or otherwise appears critically ill, seek emergency veterinary care immediately.