Mistletoe

Symptoms reported in cats

Most serious first.

1. 1
   Bradycardia, hypotension, and potential cardiovascular collapse Within hours of ingesting a toxic dose · These life-threatening cardiovascular effects are caused by the plant's lectins and phoratoxins3. Fortunately, severe heart toxicity is relatively uncommon and usually only occurs if the cat consumes a large amount of the plant.
2. 2
   Gastrointestinal upset, including vomiting and diarrhea (which can be profuse) Within hours of ingestion · If a cat only eats a small amount (like a few leaves or berries), the symptoms are typically limited to mild gastrointestinal irritation14. However, ingesting larger amounts leads to severe gastrointestinal distress.
3. 3
   Difficulty breathing or rapid, labored breathing Within hours of ingesting a toxic dose · This symptom is typically seen in severe cases of toxicity alongside cardiovascular collapse and shock.
4. 4
   Weakness, odd behavior, and dilated pupils Within hours of ingestion · The profound weakness and lethargy a cat experiences are usually secondary effects caused by the significant drop in blood pressure and the slowed heart rate.

Important notes

Mistletoe (Phoradendron spp. or Viscum spp.) is a popular holiday decoration that is highly toxic to cats. It contains toxic proteins, such as lectins and phoratoxins, which can seriously affect a cat's stomach, intestines, and heart. The berries usually have the highest concentration of these toxins. If a cat eats mistletoe, it may experience severe vomiting, diarrhea, drooling, and stomach pain. The toxins can also cause dangerous drops in blood pressure and a slowed heart rate, which can make the cat very weak or cause breathing problems. Even dried decorations or fallen berries are dangerous. Keep all mistletoe completely out of your cat's reach during the holidays. If you suspect your cat has eaten any part of a mistletoe plant, contact a veterinarian immediately.

• Toxic compounds: phoratoxins (toxic lectins) in all parts; viscotoxins in European Mistletoe; berries most concentrated
• Mechanism: lectins inhibit protein synthesis in cells; cardiovascular effects include bradycardia and hypotension
• Symptoms: vomiting, diarrhea, drooling, abdominal pain, weakness, bradycardia, low blood pressure; severe ingestion may cause collapse
• All parts are toxic — fresh plant, dried decorations, and even fallen berries on the floor
• Keep mistletoe completely out of reach during the holiday season; contact your vet if ingestion is suspected