Oleander: A Beautiful Plant With a Genuinely Dangerous Reputation

Oleander is common in warm-climate landscaping, particularly in the southern and southwestern US, valued for how easily it grows and how little water it needs — and it's also one of the plants where the toxicity warnings genuinely aren't exaggerated. It contains cardiac glycosides that directly affect heart rhythm and function, and even a small amount of leaf or flower material can cause serious effects.

Unlike some plants on this list where a small nibble is usually fine, oleander is one where the concentration of toxin means "a small amount" still warrants real concern.

Symptoms to watch for: vomiting and diarrhea initially, followed by an irregular or abnormally slow heart rate, weakness, tremors, and in serious cases, collapse or cardiac arrest.

What to do right now: any known or suspected ingestion of oleander should be treated as an emergency immediately, regardless of the amount involved. The cardiac effects of this plant are not something you can safely wait out at home to see how mild it turns out to be.

When it's an emergency: always, for any part of the plant and any amount.

## Related Reading

• Is Poinsettia Actually Toxic? Debunking the Holiday Myth
• Autumn Crocus: A Small Flower With Outsized Danger
• Hops: A Surprising and Serious Danger for Dogs

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This is general information, not a substitute for an actual assessment of your specific pet, weight, and situation. If you're ever unsure whether something your pet ate needs immediate attention, a quick video vet consultation can tell you in minutes whether to monitor at home or head to a clinic.