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Yellow Oleander
Thevetia peruviana
Yellow Oleander (Cascabela thevetia, formerly Thevetia peruviana) is closely related to common Oleander and equally dangerous. All parts — seeds, leaves, bark, flowers, and fruit — contain thevetin A and thevetin B, potent cardiac glycosides related to digitalis. Seeds are most concentrated and are responsible for the majority of reported poisonings.
Important Notes
Toxic compounds: thevetin A and thevetin B (cardiac glycosides) in all parts; seeds most concentrated
Mechanism: thevetins inhibit Na+/K+-ATPase in cardiac muscle, disrupting electrical conduction causing arrhythmias and heart block
Symptoms: vomiting, diarrhea, drooling, severe weakness, bradycardia, cardiac arrhythmias, hypotension, collapse; often fatal without treatment
Yellow Oleander seeds are particularly accessible when the fruit falls; the decorative yellow flowers are also attractive
Any suspected ingestion is a veterinary emergency
Potentially Toxic Parts
Stem
Bark
Seed
Entire Plant
Leaf
Flower
Fruit
Root
Sap
Possible Symptoms Reported in Cats
Bradycardia (abnormally slow heart rate) or tachycardia (rapid heart rate), and severe arrhythmias
Cardiac · Expected within the first 2 hours after exposure
Hyperkalemia (elevated potassium levels in the blood)
Hematological · Within the first 2 hours after exposure
Vomiting, diarrhea, excessive drooling, and abdominal pain
Gastrointestinal · Within the first 2 hours after exposure
Weakness and lethargy
Neurological · Within the first 2 hours after exposure
Tremors and seizures
Gastrointestinal · Often within the first few hours, progressing as the toxicosis worsens
Respiratory changes and difficulty breathing
Respiratory · Usually presents as the toxicity progresses (within hours)
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.