←
Lily of the Valley
Convallaria majalis
Lily of the Valley (Convallaria majalis) is one of the most dangerous plants for cats. Despite its delicate appearance, every part — flowers, leaves, stems, berries, and even the water in a vase — contains potent cardiac glycosides including convallatoxin, convalloside, and over 30 related compounds. These affect the heart in a manner similar to Foxglove, and even tiny amounts can be lethal.
Important Notes
Toxic compounds: convallatoxin, convalloside, and 30+ related cardiac glycosides; highest in flowers and berries
Mechanism: cardiac glycosides inhibit Na+/K+-ATPase in heart muscle, disrupting electrical conduction and causing severe arrhythmias
Symptoms: vomiting, drooling, bradycardia (dangerously slow heart rate), hypotension, cardiac arrhythmias, weakness, collapse; can be fatal
All plant parts are hazardous — even the water in a flower vase can cause toxicity
Any ingestion is a veterinary emergency; do not wait for symptoms to develop
Potentially Toxic Parts
Root
Entire Plant
Flower
Possible Symptoms Reported in Cats
Bradycardia (a sudden, significant decrease in heart rate) and severe cardiac arrhythmias (such as Atrioventricular or AV block)
Cardiac · Variable latent period depending on the dose;
Vomiting, diarrhea (which may contain blood), abdominal pain/discomfort, and trembling
Gastrointestinal · Variable latent period depending on the dose;
Seizures and tremors
Gastrointestinal · Variable; usually develops as the cardiovascular depression worsens
Disclaimer: This summary was compiled from multiple sources and is for informational use only. It is not a diagnosis or treatment plan. Toxicity can vary based on the substance, amount, plant part, and individual cat. If you think your cat may have been exposed to a toxic substance, contact a veterinarian right away.