Are Hydrangeas Poisonous to Cats? Yes, Because of Cyanide

hydrangeas with cat — Really, you shouldn't have these flowers anywhere near your fur baby. Cyndi Monaghan / Getty Images

Are hydrangeas poisonous to cats? Yes, extremely.

While admired for their colorful blooms and lush, ball-shaped flowers, hydrangeas are considered toxic plants for cats. If a cat eats part of a hydrangea plant, especially the leaves or flowers, it may suffer from hydrangea poisoning.

These plants contain cyanogenic glycosides, a compound that can release cyanide when metabolized. The most common form, called amygdalin, can lead to serious issues in your cat’s digestive system and beyond.

5 Signs of Hydrangea Poisoning in Cats

Hydrangeas look beautiful in a garden but should be nowhere near your cat. Hans Georg Roth / Getty Images

If your cat spends time outdoors or around floral decorations, watch for symptoms like:

Vomiting
Diarrhea
Lethargy
Difficulty breathing
Skin irritation (in cats with sensitive skin)

More serious symptoms can include tremors, confusion, and collapse, especially in severe cases. If ingested hydrangea is suspected, seek veterinary care immediately.

Diagnosis and Treatment

A veterinarian will assess hydrangea poisoning in cats based on exposure history and clinical signs. Treatment usually involves supportive care like:

Induce vomiting or gastric lavage (aka stomach pumping) to remove plant material
Anti-nausea medications to control vomiting
Intravenous fluids to prevent dehydration

In rare severe cases, the veterinarian will provide intensive supportive care rather than a direct antidote (no specific antidote exists for cyanide from hydrangeas).

The best course is rapid action. Call your vet or the Pet Poison Helpline as soon as you suspect exposure.

Preventing Hydrangea Poisoning

Cat with hydrangeas — This is the correct attitude for a cat to have regarding hydrangeas. oxygen / Getty Images

Pet owners can take steps to prevent hydrangea poisoning:

Avoid planting hydrangea macrophylla or other hydrangea types in your garden
Choose alternative plants that are cat-safe
Keep cats away from colorful flowers used in bouquets or wreaths
Educate houseguests about toxic flowers

Hydrangeas, also called seven bark, are beautiful but risky. The large clusters of vibrant flowers may look inviting, but they can threaten pet health.

We created this article in conjunction with AI technology, then made sure it was fact-checked and edited by a HowStuffWorks editor.