Lily of the Valley Bush Poisoning in Cats

Lily of the valley bush is toxic to cats and other animals due to its production of grayanotoxins. These toxins produce gastrointestinal, nervous system, respiratory, and cardiac symptoms which can result in death. Ingestion of even a small amount of the plant can result in serious complications as it is highly toxic.

Lily of the valley bush should not be confused with lily of the valley, which is a different plant. Due to similarities in their small dainty flowers, similar common names have been adopted. Lily of the valley bush, scientific name Pieris japonica also goes by the common names andromeda japonica and pieris and is from the plant family Ericaceae. It is a round shrub growing about 9 to 10 feet tall and 6 to 8 feet wide with glossy leaves and producing abundant small white, pink, or reddish flowers in late winter and spring. It is popular as an ornamental as it grows in shady locations and because of its early blooming cycle.

Symptoms vary depending on the amount of the plant consumed.

Small amounts of lily of the valley ingestion may result in:

• Salivation/drooling
• Sweating from foot pads and nose
• Vomiting
• Diarrhea
• Dizziness
• Weakness
• Twitching
• Tingling, burning, pins and needles sensations
• Numbness
• Low blood pressure

Ingestion of large amounts can result in:

• Loss of coordination
• Severe muscular weakness
• Bradycardia
• Coma
• Death

Lily of the valley bush is an ornamental plant found cultivated in gardens for its ornamental qualities. It contains a toxin called grayanotoxin which is a neurotoxin that binds sodium channels in cell membranes, causing electrical currents in nerve and muscle cells to be disrupted, similar to what occurs with alkaline poisoning. All parts of the plant contain toxins and ingestion can cause severe illness in our cat. Grayanotoxins cause symptoms of burning in the mouth, making the lily of the valley bush unappetizing and most animals will not choose to ingest large quantities. However, due to its high toxicity and the small size of a cat, only a small amount is required to induce serious toxic results.

If your cat has ingested lily of the valley bush, seek veterinary assistance immediately due to the toxic nature of this plant. If possible, take a sample of the plant to the veterinarian with you to confirm identification. Your veterinarian will perform a physical exam and take a medical history of your cat to determine any pre-existing conditions that may affect the progress of toxicity and ascertain vital signs and symptoms of poisoning. Blood pressure, oxygen levels and heart rhythm will be monitored to determine the extent of poisoning. Blood and urine tests may be ordered to identify organ functioning. 

Grayanotoxins are metabolized quickly, and if only a small amount was ingested, it may pass through the system within a few hours. Symptoms may cease within two to nine hours, and a full recovery made within 24 hours. If a large amount was ingested, death may occur within a few days without treatment.

If ingestion was recent, inducing vomiting or gastric lavage followed by the administration of activated charcoal may limit the amount of toxins that pass through the gastrointestinal tract and are absorbed by your cat’s body. Your veterinarian will also provide supportive therapy in the form of oxygen therapy for respiratory distress and intravenous fluid therapy to prevent dehydration. Atropine may be administered for bradycardia and sodium channel blockers may be used to treat heart symptoms. Your veterinarian may administer additional medication to support organ function and ease symptoms.

Prognosis in severe cases is guarded.

Ensure that reexposure to the plant causing the toxicity does not occur. Your cat may need a special diet to facilitate gastrointestinal healing after poisoning and address symptoms. Medication to ensure a return to normal organ functioning may be prescribed. As this toxic plant is metabolized quickly, your pet should recover from the poisoning symptoms relatively quickly. However, if damage to organs or organ systems occurred, ongoing monitoring and treatment by yourself and your veterinarian will be required.