Hydrangeas are poisonous to cats. All parts of the hydrangea plant, especially the leaves and flowers, contain cyanogenic glycosides, which can release cyanide when metabolized, leading to toxic effects. If a cat ingests hydrangea, symptoms can include vomiting, diarrhea, weakness, depression, and abdominal pain. Severe cyanide poisoning is rare but possible, so any ingestion of hydrangea by a cat should prompt a visit to the veterinarian as soon as possible for evaluation and treatment.

Toxic Components

• Hydrangeas contain amygdalin, a cyanogenic glycoside that can cause cyanide poisoning.
• Cyanide impairs the body's ability to use oxygen properly.

Symptoms in Cats

• Vomiting and diarrhea (sometimes with blood)
• Weakness or lethargy
• Depression
• Abdominal pain
• In cases of severe poisoning, pale or blue gums and stiff limbs can occur.

What to Do

• If ingestion is suspected, seek immediate veterinary care.
• Do not induce vomiting without veterinary guidance.
• Bringing a sample of the plant to the vet can help with identification and treatment.

Cats are more susceptible to hydrangea toxicity than dogs due to their smaller body size. Although serious poisonings are rare, even small amounts can cause gastrointestinal upset.