Lily of the Valley

Symptoms reported in cats

Most serious first.

1. 1
   Bradycardia and severe cardiac arrhythmias (e.g. AV block) Variable latent period depending on the dose; · This is the most dangerous consequence of Lily of the Valley toxicity and is caused by the plant's cardiac glycosides2. These toxins alter how the cardiac muscle contracts and disrupt electrical conduction.
2. 2
   Vomiting, diarrhea (which may contain blood), abdominal pain/discomfort, and trembling Variable latent period depending on the dose; · These symptoms are primarily triggered by the irritant saponins found throughout the plant12. The severe irritation of the gastrointestinal tract often precedes more dangerous systemic cardiovascular issues.
3. 3
   Seizures and tremors Variable; usually develops as the cardiovascular depression worsens · Seizures and trembling are secondary clinical signs that manifest as the toxins profoundly depress the cardiovascular system and disrupt cellular functions.

Important notes

Lily of the Valley (Convallaria majalis) is one of the most dangerous plants you can have around cats. Even though it looks small and delicate, every single part of the plant—including the flowers, leaves, roots, and berries—is highly toxic. Even the water in a vase holding cut flowers becomes poisonous. The plant contains strong poisons called cardiac glycosides. These toxins directly attack the heart muscle, changing how the heart beats and causing dangerous, irregular heart rhythms. It also contains compounds that severely bother the stomach and intestines. Unlike true lilies, it does not cause kidney failure, but it is just as deadly. Even a tiny bite can cause severe issues. A poisoned cat may suddenly vomit, have stomach pain or bloody diarrhea, and drool heavily. As the heart is affected, the cat's heart rate may drop dangerously low, and they may show extreme weakness, trembling, or seizures. Any bite is a life-threatening emergency. Please immediately contact a veterinarian or emergency animal hospital.

• 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