Is Hydrangea Toxic to Cats and Dogs?
Hydrangea plants are toxic to both cats and dogs. According to the ASPCA, these popular garden shrubs contain a compound called a cyanogenic glycoside. This substance is present in all parts of the plant, including the leaves, stems, and colorful flower heads.
While the term cyanogenic glycoside can sound alarming, the ASPCA notes that serious cyanide poisoning from eating this plant is rare in pets. It is more common for a cat or dog to experience gastrointestinal upset, such as vomiting or diarrhea, after ingesting parts of a hydrangea.
Hydrangea: what the ASPCA database lists
| ASPCA entry | Hydrangea |
|---|---|
| Other common names | Hortensia, Hills of Snow, Seven Bark |
| Scientific name | Hydrangea arborescens |
| Family | Hydrangeaceae |
| Toxic to | Toxic to Dogs, Toxic to Cats, Toxic to Horses |
| Non-toxic to | None listed |
| Toxic principles | Cyanogenic glycoside |
| Clinical signs listed | Vomiting, depression, diarrhea. Cyanide intoxication is rare – usually produces more of a gastrointestinal disturbance. |
What the ASPCA says about hydrangea
The American Society for the Prevention of Cruelty to Animals (ASPCA) identifies Hydrangea arborescens as toxic to cats, dogs, and horses. This plant is also known by other common names, including Hortensia, Hills of Snow, and Seven Bark. All parts of the hydrangea are considered toxic.
The toxic principle is a cyanogenic glycoside. When a pet eats the plant, this compound can lead to a few potential clinical signs. The ASPCA lists the following symptoms associated with hydrangea ingestion:
- Vomiting
- Depression
- Diarrhea
The organization clarifies that while cyanide intoxication is possible, it is rare. The more typical reaction for a pet that has eaten a small amount of hydrangea is gastrointestinal disturbance.
What hydrangea toxicity means in a home with pets
Having a hydrangea in your yard or home means you need to be cautious if you also have pets. A curious cat or dog might chew on the leaves, flowers, or stems out of boredom or exploration. Even a small amount of the plant material can be enough to cause stomach upset.
Because the entire plant contains the toxic compound, there is no safe part for a pet to nibble on. This includes fallen leaves or wilted blooms that may be on the ground. The most common risk is not severe poisoning but rather the discomfort and illness associated with vomiting and diarrhea. A pet’s individual reaction can vary.
Keeping cats, dogs, and this plant apart
The most effective way to prevent a problem is to make sure your pets cannot access hydrangea plants. For outdoor shrubs, consider using pet-safe fencing or other barriers to create a boundary around the garden bed. You can also plant them in an area of the yard your pets do not use.
If you bring cut hydrangeas indoors for a floral arrangement, place the vase well out of your pet’s reach. A high shelf or a room with a closed door are safer options than a low coffee table. Do not use dried hydrangea flowers in home decor where a pet could reach them. Always supervise your pets, especially puppies and kittens, around plants. Providing plenty of safe toys and enrichment can also help reduce their interest in chewing on household plants.
When to call your vet
If your pet chewed or ate part of this plant, call your veterinarian or an animal poison control line. Note which plant and which part, how much may be gone and when, and take a photo or a piece of the plant with you.
If you suspect your cat or dog has eaten any part of a hydrangea plant, contact your veterinarian or the ASPCA Animal Poison Control Center immediately. Be prepared to share what part of the plant was eaten, how much, and when it happened. Do not try to induce vomiting or give any home remedies unless specifically instructed to do so by a veterinary professional.
Emergency signs: go now
- Collapse, fainting or severe weakness
- Seizures, tremors or trouble standing
- Trouble breathing or blue, gray or very pale gums
- Repeated vomiting or retching, or a swollen, painful belly
- Any known contact with a substance listed as toxic, even before signs appear
Book an appointment soon
- Vomiting or diarrhea that lasts or keeps coming back
- Not eating or drinking, or drinking much more than usual
- Drooling, pawing at the mouth or a swollen face
- Lethargy, hiding or acting unlike themselves
ASPCA Animal Poison Control Center: (888) 426-4435 (a consultation fee may apply). Your own vet or nearest emergency clinic is always a good first call.
Sources
Last checked October 21, 2026. Listings and guidance can change; your veterinarian knows your pet’s health history.