Is it toxic to dogs?
Mistletoe
Phoradendron leucarpum (also listed as Phoradendron flavescens) · Santalaceae (formerly Viscaceae)
Also called American mistletoe, Christmas mistletoe, Eastern mistletoe
Toxic to dogs
Severity: Severe
Yes. The ASPCA lists American mistletoe as toxic to dogs. A berry or two usually means vomiting and diarrhea, but large amounts can lower blood pressure and heart rate, and veterinary sources say deaths are possible.
- Toxic parts
- All parts, Berries
- Toxic compounds
- Toxalbumin, phoratoxin and viscumin (lectins, phoratoxins)
- Where you’ll find it
- Outdoors / wild
- When signs start
- Merck describes serious effects within hours of a toxic dose.
Signs of poisoning
- Vomiting
- Diarrhea
- Low blood pressure (rare)
- Difficulty breathing
- Low heart rate
- Stumbling, collapse or seizures after large amounts
Why it’s harmful to dogs
Mistletoe is the semi-parasitic plant that grows in clumps on tree branches and gets cut into holiday sprigs with white berries. This page covers American mistletoe (Phoradendron leucarpum, listed by the ASPCA under the synonym Phoradendron flavescens), the native North American plant the ASPCA rates. European mistletoe, Viscum album, is a separate plant in a different genus, and VCA Animal Hospitals say it is the more poisonous of the two.
The ASPCA lists the American plant as toxic to dogs, naming toxalbumin, phoratoxin and viscumin, which are lectins and related proteins. The signs it records are vomiting, diarrhea, low blood pressure (rare), difficulty breathing and a low heart rate. Pet Poison Helpline says eating the plant or berries commonly causes stomach upset, and large amounts can lead to low blood pressure and a stumbling gait.
VCA warns that large ingestions can bring on collapse, low blood pressure, wobbliness, seizures and even death, and the Merck Veterinary Manual describes deaths from cardiovascular collapse within hours of a toxic dose. That is why this page rates mistletoe as severe, even though most nibbles end with an upset stomach.
If your dog ate mistletoe
Pull any sprigs or berries from your dog's mouth and call your vet or ASPCA Animal Poison Control at (888) 426-4435 or Pet Poison Helpline at (855) 764-7661 (US; fees may apply) promptly. Don't wait to see what happens, especially if your dog ate more than a berry or two.
Go to an emergency clinic if your dog vomits repeatedly, stumbles, seems weak, or has trouble breathing. Outside the US, call your local emergency vet. Don't try to make your dog vomit at home. Take a sprig or photo, and note how much was eaten and when.
Keeping your dog safe
Hang mistletoe from a high hook and keep it out of dogs' reach at all times. Don't leave sprigs on a mantel, table, shelf or in a gift pile. Check the floor under hanging sprigs every day, since berries and leaves drop as they dry.
A fake sprig is a simple swap. For living greenery, a Christmas cactus or rosemary is friendlier. See holly and poinsettia for other holiday plants to keep out of reach.
Dog-safe alternatives
Frequently asked questions
Is American or European mistletoe more dangerous?
VCA Animal Hospitals say American mistletoe is less poisonous than European mistletoe (Viscum album). Both can cause serious illness in large amounts, so keep either out of reach.
Are the berries the only toxic part?
No. The Merck Veterinary Manual says the toxic compounds are found in all parts of the plant.
How quickly can mistletoe poisoning become serious?
Merck describes serious cardiovascular effects within hours of a toxic dose, so call your vet right away rather than watching and waiting.
Written from veterinary sources by the Pawsplained editorial team. Not yet reviewed by a veterinarian; this is general information, not a diagnosis or treatment plan. Updated Oct 30, 2026. Editorial policy