Is European Mistletoe Poisonous? – Viscum album Toxicity Guide

European mistletoe (Viscum album) is toxic to humans, dogs, and cats. It is distinct from American mistletoe (Phoradendron spp.) and is considered more toxic. The berries, leaves, and stems all contain harmful compounds. While nibbling a single berry is unlikely to cause fatal illness in a healthy adult, significant ingestion can cause serious symptoms. Children and small pets face greater risk from a smaller amount.

What Makes European Mistletoe Toxic?

European mistletoe contains two main groups of harmful compounds:

• Lectins (mistletoe lectins or viscumin): Proteins that can inhibit protein synthesis in cells. Found throughout the plant, with higher concentrations in the berries.
• Viscotoxins: Small proteins that can affect heart function and cellular integrity. Found in the leaves and stems.

Both compound groups are absent from or present in much lower concentrations in American mistletoe, which is why European mistletoe is considered more dangerous.

Which Parts Are Most Dangerous?

The white, waxy berries are the primary concern for accidental ingestion because they attract curious children and pets. The leaves and stems also contain viscotoxins. The entire plant should be treated as toxic.

Symptoms of European Mistletoe Ingestion

Dogs and cats: Vomiting, diarrhea, abdominal pain, and lethargy are the most common signs after small ingestion. Larger amounts may cause low blood pressure, an unsteady gait, and cardiovascular effects.

Humans and children: Small ingestion typically causes nausea, vomiting, stomach pain, and diarrhea. Significant ingestion, or herbal preparations made from concentrated plant material, can cause low blood pressure, slowed heart rate, and in documented cases, death. Children are at greatest risk because the berries are visually appealing.

What to Do If Someone Ingests European Mistletoe

1. Identify how much was consumed and what part of the plant, if possible.
2. Remove any remaining plant material from the mouth.
3. Rinse the mouth with water.
4. Call poison control at 1-800-222-1222 (US) or your vet immediately, even for small amounts.
5. Do not wait for symptoms before seeking guidance.
6. Do not induce vomiting unless a medical professional instructs you to.

Dose matters with mistletoe. A few berries may cause only mild GI upset in an adult but could produce a more serious reaction in a small child or a small dog. Always call poison control rather than attempting to assess the risk yourself.

Safe Handling

• Keep mistletoe completely out of reach of children and pets, particularly during holiday decorating.
• Do not use European mistletoe as decoration in homes with young children or animals that explore freely.
• Dispose of fallen berries promptly.
• Wear gloves when handling the plant and wash hands thoroughly afterward.
• Never prepare European mistletoe tea or herbal preparations without professional guidance. Concentrated preparations have caused documented deaths.

Frequently Asked Questions

Is European mistletoe more dangerous than American mistletoe? Yes. Viscum album contains lectins and viscotoxins not present in significant amounts in American mistletoe (Phoradendron spp.), giving it a more serious toxicity profile.

How many berries are dangerous? There is no established safe number. The dose depends on the person’s or animal’s size and the specific plant’s lectin concentration. Call poison control immediately if berries are ingested.

Is mistletoe toxic to cats? Yes. Cats that ingest mistletoe berries or leaves may experience vomiting, diarrhea, lethargy, and low blood pressure. Contact your vet immediately.

Can I hang European mistletoe at Christmas if I have pets? Only if it is placed completely out of reach of all pets, including climbers. Artificial mistletoe is the safest option for homes with dogs, cats, or young children.