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Is Mistletoe Toxic to Dogs? Berries and Leaves Explained

PawAI Lab
6 min read

Learn whether mistletoe berries and leaves pose a serious risk to dogs, which compounds are responsible, why the verdict is "toxic," and what steps a veterinarian may recommend.

Quick Answer

Yes, mistletoe is toxic to dogs. The plant contains compounds known as toxalbumins and phoratoxins (and, in European mistletoe, viscotoxins), which can affect the gastrointestinal tract, heart, and nervous system. Ingestion can cause vomiting and diarrhea and, in severe cases, cardiovascular collapse and seizures. Contact a veterinarian or animal poison-control service promptly after any known or suspected exposure, even if only a small amount was eaten.

Before using any tool, contact a veterinary professional if your dog may have eaten mistletoe.

  • US: ASPCA Animal Poison Control (888-426-4435) or Pet Poison Helpline (855-764-7661)
  • UK: Animal PoisonLine (01202 509000) or your nearest veterinary emergency clinic
  • Canada: ASPCA Animal Poison Control (888-426-4435) or Pet Poison Helpline (855-764-7661)
  • AU: Animal Emergency Centre or your regular vet
  • EU: Contact your nearest veterinary emergency service

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Safety Verdict

Toxic. Mistletoe is recognized as a toxic plant for dogs. American mistletoe (Phoradendron species) contains phoratoxins and toxalbumins, while European mistletoe (Viscum album) contains viscotoxins and viscumin, a toxalbumin. These compounds can irritate the digestive tract, affect the cardiovascular system, and, in significant ingestions, impact the nervous system.

All parts of the plant are considered toxic, with the berries often posing the greatest concern because they are attractive and accessible. Although many real-world exposures produce mild gastrointestinal signs, the potential for more serious effects means mistletoe should never be treated as safe for dogs.

What Should the Owner Do Now?

  1. Contact a veterinarian or animal poison-control service immediately, especially if berries were eaten.
  2. Do not induce vomiting unless a veterinarian or poison-control professional directly instructs you to.
  3. Do not give food, milk, salt, oil, charcoal, or any home remedy. None of these are proven treatments for mistletoe toxicity and some may cause harm.
  4. Collect relevant details (see the section below) so the veterinary team can assess exposure accurately.
  5. Follow the veterinarian's instructions regarding examination, monitoring, or supportive care.

What Signs May Occur?

Signs of mistletoe ingestion in dogs may develop within a few hours. Absence of early signs does not necessarily rule out risk, especially when the amount eaten is uncertain.

Common signs may include:

  • Drooling
  • Vomiting
  • Diarrhea
  • Reduced appetite
  • Lethargy or depression

When a larger amount is ingested, more serious signs may appear and can include:

  • Persistent or severe vomiting and diarrhea
  • Changes in heart rate or blood pressure (associated with cardiovascular effects)
  • Difficulty breathing
  • Seizures
  • Weakness or collapse (cardiovascular collapse in severe cases)

Because mistletoe can affect multiple body systems, any signs beyond mild stomach upset warrant immediate veterinary attention.

What Information Should Be Ready?

When you contact a veterinarian or poison-control service, having the following details available can help them assess the situation more efficiently:

  • Dog's details: species, breed, approximate age, and body weight
  • Plant part consumed: berries, leaves, or stems
  • Estimated amount: best guess of how much plant material was eaten
  • Time of ingestion: when exposure occurred, or the window during which it may have happened
  • Current symptoms: any drooling, vomiting, diarrhea, lethargy, or breathing changes
  • Plant identification: whether the plant is American or European mistletoe, if known
  • Medical history: any pre-existing heart conditions, seizure disorders, and current medications

Provide honest estimates rather than precise numbers. The veterinary team can work with approximate information.

Differences That May Affect Risk

Several factors can influence how mistletoe affects an individual dog:

  • Plant species: American and European mistletoe contain related but different toxic compounds, which can influence the type and severity of signs.
  • Plant part: Berries are often the main concern, but leaves and stems are also considered toxic.
  • Amount ingested: Larger ingestions are associated with more severe signs.
  • Body size: Smaller dogs may be more affected by a given amount of plant material.
  • Pre-existing conditions: Dogs with heart disease or seizure disorders may be more vulnerable to cardiovascular and neurological effects.

When to Contact a Veterinarian

Contact a veterinarian or animal poison-control service immediately if your dog has eaten mistletoe berries, leaves, or stems. Do not wait for symptoms to appear.

Emergency signs that require urgent veterinary attention include:

  • Persistent vomiting or diarrhea
  • Changes in heart rate, weakness, or collapse
  • Seizures
  • Difficulty breathing
  • Signs of abdominal pain

Non-urgent follow-up: If only a very small amount of leaf was eaten and your dog appears normal, professional guidance is still recommended to confirm whether monitoring at home is appropriate.

FAQ

Are mistletoe berries poisonous to dogs?

Yes, mistletoe berries are toxic to dogs. They contain compounds such as toxalbumins and phoratoxins that can affect the digestive tract, heart, and nervous system. Most ingestions cause vomiting and diarrhea, but larger amounts can lead to seizures or cardiovascular collapse. Any ingestion should be discussed with a veterinarian.

What happens if a dog eats mistletoe leaves?

If a dog eats mistletoe leaves, the toxic compounds they contain can cause drooling, vomiting, diarrhea, and lethargy. In larger ingestions, the effects may extend to the heart and nervous system. Contact a veterinarian or poison-control service for guidance.

Is mistletoe safe for dogs at Christmas?

Mistletoe is not safe for dogs to eat, so it should be kept out of reach during the holidays. Because the berries are attractive and accessible, decorative mistletoe warrants caution, particularly for dogs that tend to chew or eat plant material.

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Disclaimer

This article and the PawAI Toxicity Checker provide general safety information and cannot determine an individual pet's toxicity risk or replace a veterinarian or animal poison-control service. If exposure may have occurred, contact an appropriate professional promptly, even if your pet appears well.