Reference
Is Oleander Poisonous to Pets and People?
The short answer
Yes. The ASPCA lists oleander (Nerium oleander) as toxic to dogs, cats, and horses, with the toxic principle being cardiac glycosides that can cause drooling, abdominal pain, diarrhea, colic, depression, and death. All parts of the plant are considered poisonous.
It is also poisonous to people - medical reviews describe all parts as toxic and note that ingestion can cause gastrointestinal upset and dangerous heart-rhythm disturbances. If a pet eats any part, call your vet or ASPCA Animal Poison Control (888-426-4435); if a person ingests it, call your local poison center or emergency services immediately. Never invent a 'safe' amount.
Why oleander is dangerous
Oleander is a widely planted evergreen shrub valued for its showy flowers and drought tolerance, especially in warm climates. Its danger comes from cardiac glycosides - compounds that interfere with the heart's normal electrical activity, similar in mechanism to digitalis/foxglove toxins.
The ASPCA lists oleander as toxic to dogs, cats, and horses. All parts of the plant contain the toxin, so there is no safe portion for an animal or person to chew or swallow.
Signs of poisoning
In pets, the ASPCA lists clinical signs including drooling, abdominal pain, diarrhea, colic, depression, and death. Because the toxin affects the heart, serious cases can involve abnormal heart rate and rhythm.
In people, medical reviews of Nerium oleander poisoning describe all parts as poisonous and report symptoms such as nausea, vomiting, abdominal pain, and diarrhea, followed by cardiac effects including irregular or slowed heartbeat. This is a plant where curiosity - a child tasting a leaf, someone using a stem as a food skewer, or inhaling smoke from burning clippings - has caused serious harm.
What to do and how to be safe
If a pet eats any part of an oleander, contact your veterinarian or the ASPCA Animal Poison Control Center at (888-426-4435) immediately. If a person ingests it, call your local poison control center or emergency services right away rather than waiting for symptoms.
When handling oleander in the garden, wear gloves, keep clippings away from pets and children, and do not burn the prunings or compost them where animals graze. If you have pets or young children, siting or removing this shrub with them in mind is worth considering. To vet any plant before planting, see our page on how to check whether a plant is pet-safe.
Sources
Reviewed 2026-07-18. We cite university Extension, government, and established horticultural sources — and never invent pesticide rates or dangerous treatments.
- ASPCA - Toxic and Non-Toxic Plants: Oleander (Nerium oleander) — Lists oleander (Nerium oleander) as toxic to dogs, cats, and horses with the toxic principle cardiac glycosides, and clinical signs of drooling, abdominal pain, diarrhea, colic, depression, and death.
- Bandara, Weinstein, White & Eddleston (2010), Toxicon - Review of Nerium oleander poisoning — Peer-reviewed review describing Nerium oleander as containing cardiac glycosides with all parts toxic to humans, causing gastrointestinal effects and cardiac dysrhythmias on ingestion.