- A holiday hazard
- Within hours
- Affects: Gut & heart
Why this verdict for cats
Mistletoe is toxic to cats and can affect the heart and blood pressure beyond simple stomach upset. Treat ingestion of more than a berry or two as an emergency.
Warning signs to watch for
- Vomiting
- Drooling
- Weakness
⚠ If your cat ate mistletoe
Act immediately — don't wait for symptoms.
- Call your vet or a pet poison helpline right away.
- Note how much was eaten and when.
- Do not induce vomiting unless a professional tells you to.
Mistletoe earns its place on the Christmas hazard list, though its reputation is slightly out of proportion to the usual outcome. The berries and leaves are genuinely toxic, but most household exposures involve a small amount of a decorative sprig.
How much is safe?
Small nibbles typically cause stomach upset. Larger ingestions — a handful of berries or a good mouthful of leaves — are where the more serious effects appear. American mistletoe (Phoradendron) and European mistletoe (Viscum) differ slightly, with the European variety generally considered more potent. Modern decorative sprigs often have plastic berries, which changes the problem from poisoning to a possible obstruction, so check what your pet actually ate.
What happens if a cat eats too much?
Drooling, vomiting, diarrhoea and abdominal discomfort are the common picture. With significant amounts the toxins can affect the cardiovascular system, producing weakness, a slow heart rate, low blood pressure and collapse, and in rare cases wobbliness or difficulty breathing. Cats tend to be affected at smaller amounts simply because they are smaller.
⚠ What to do if your cat ate mistletoe
Call your vet or a poison line with an estimate of the amount and, if you can, whether the berries were real (ASPCA 888-426-4435 · Pet Poison Helpline 855-764-7661). A small nibble is usually monitored at home with attention to hydration; larger amounts warrant being seen. Hang decorations well out of reach, and remember that fallen berries end up at exactly nose height.
⚠️ Worried your pet got into this?
Frequently asked questions
Is mistletoe worse than poinsettia?
Yes. Poinsettia's reputation is largely a myth — it causes mild mouth and stomach irritation. Mistletoe, holly berries and lilies are the Christmas plants that deserve real caution, with lilies being by far the most dangerous for cats.
What if the berries were plastic?
Then the concern is obstruction rather than poisoning, especially in a small dog or a cat. Still worth a call.
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 July 31, 2026.
Sources
- ASPCA — People Foods to Avoid Feeding Your Pets
- American Kennel Club — Dog Nutrition
- Pet Poison Helpline — Poison List