Is Mistletoe Toxic to Cats?

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  • Is mistletoe toxic to cats?

    Mistletoe is toxic to cats. The toxic compounds are phoratoxin, gamma-aminobutyric acid, phenols, phenethylamines, phenylpropanoids, polysaccharides, and flavonoids which can cause gastrointestinal disturbances and in rare cases hypotension and bradycardia.

    What is mistletoe?

    What is mistletoe?

    • Name: American or European Mistletoe
    • Scientific names: Phoradendron serotinum (North American) and Viscum album (European)
    • Toxicity: Toxic to cats
    • Toxic compounds: Phoratoxin, gamma-aminobutyric acid, phenols, phenethylamines, phenylpropanoids, polysaccharides, and flavonoids
    • Severity: Mild to moderate
    • Toxic parts: All parts of P. serotinum are toxic, all parts of V. album apart from the berries

    Mistletoe is a group of parasitic plants that live on trees and is most commonly associated with Christmas and kissing under the mistletoe.

    Birds eat the edible fruit which passes out of the body and onto tree branches via the feces. The seed releases a sticky substance called viscin, which dries and forms a cement to ensure it remains in place. Most seeds germinate in spring and send out a root into the host tree where it steals water and nutrients.

    Kissing under the mistletoe origins

    The origins of kissing under the mistletoe come from Norse mythology where the goddess Frigg, who took an oath from every object on earth, that they would not hurt her son, Balder (brother of Thor).  Because Balder was thought to be invulnerable, the gods would amuse themselves by throwing arrows and darts at him, none of which caused harm.

    Loki, god of mischief went in disguise to Frigg and asked ‘have all things sworn to spare Balder?’, to which she replied ‘East of Valhalla grows a plant called mistletoe; it seemed to me too young to swear’. Loki found some mistletoe and created a toxin-filled dart which he took to a circle of gods shooting at Balder. Hod, the blind brother of Balder was on the outside.

    Loki asked ‘Why do you not shoot at Balder?

    Hod replied ‘Because I do not see where he stands; besides I have no weapon.’

    Loki said ‘Do like the rest and show Balder honour, as they all do. I will show you where he stands, and do you shoot at him with this twig.’

    Hother took the mistletoe and hurled it at Balder, killing him. Frigg persuaded the gods to bring Balder back to life with the promise of wizardry and kisses. The gods made mistletoe promise that it would never again do an uncharitable deed but would forever be consecrated to acts of happiness and usefulness and Frigg was given the authority to hold mistletoe up to its pledge. A different version recounts that Frigg declared mistletoe a symbol of love rather than scorn, and vowed to kiss everyone that passed underneath it.

    Symptoms of mistletoe poisoning in cats

    • Drooling
    • Vomiting
    • Diarrhea
    • Difficulty breathing
    • Drop in blood pressure (hypotension)
    • Slow heart rate (bradycardia)

    Treatment

    If ingestion was recent, gastric decontamination (removal of the toxin from the gastrointestinal tract by inducing vomiting or pumping the stomach).

    Supportive and symptomatic care may include fluids to prevent or treat dehydration and anti-nausea medication.

    What other Christmas plants are toxic and non-toxic to cats?

    • Holly – Toxic
    • Poinsettia – Mildly toxic
    • Ivy – Toxic
    • Christmas trees – Fir and spruce; non-toxic, pine; toxic
    • Jerusalem cherry – Toxic
    • Amaryllis – Toxic
    • Lilies (Lilium and Hemerocallis) – Highly toxic
    • Christmas cactus – Non-toxic

    Prevention

    Keep plants and flowers which are toxic to cats out of the home, especially if your cat is prone to nibbling plants.

    Author

    • Julia Wilson is the founder of Cat-World, and has researched and written over 1,000 articles about cats. She is a cat expert with over 20 years of experience writing about a wide range of cat topics, with a special interest in cat health, welfare and preventative care. Julia lives in Sydney with her family, four cats and two dogs. Full author bio