Is Oleander Poisonous?

A 2025 literature review in the journal Toxins describes oleander, Nerium oleander, as one of the most toxic ornamental plants, with its dangerous effects attributed primarily to a group of cardiac glycosides, the most significant being oleandrin. A University of Florida IFAS Extension publication, citing an American Medical Association handbook, says all parts of the oleander plant contain two toxic principles identified as glycosides, and that this extremely toxic plant can poison livestock and humans at any time of the year. A 2023 case report in Arhiv za higijenu rada i toksikologiju notes that oleandrin is present in the seeds, roots, leaves, flowers, branches and stem, and cannot be inactivated by drying and cooking the leaves.

The 2025 Toxins review says the cardiac glycosides in oleander exert powerful effects on the cardiovascular system, leading to symptoms ranging from nausea and abdominal pain to severe arrhythmias and sudden cardiac death. It says patients may also present with confusion, drowsiness or even seizures, and that contact with oleander sap can lead to skin irritation or dermatitis, particularly in sensitive individuals. It describes supportive care, gastric decontamination and digoxin-specific antibody fragments as essential treatments, while noting that limited access to those antibody fragments, delays in intervention and insufficient supportive care remain significant complicating factors.

Smoke from burned oleander has also been linked to poisoning. A 2025 case report in Frontiers in Veterinary Science says oleander contains more than 30 different toxic cardiac glycosides, that intoxication can occur through ingestion or inhalation in several species, and that 76 of 205 beef cattle died within 30 hours after oleander clippings were burned.