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Oleander – how to identify this poisonous plant and diagnose/treat poisoning.

Nerium oleander leaves and pink flowers

About the Oleander (Nerium oleander) of the Dogbane (Apocynaceae) Family

The poisonous Oleander shrub (or small tree) grows to about 9 meters (27 feet), with alternate, very straight, thick, leathery, dark green, long (2-8 inches), narrow (1 inch), lance-shaped leaves. Leaves typically grow in pairs or whorls of three.  Mature plants have grayish bark.  Nerium oleander flowers may be white, yellow, red, pink, or intermediate colors and grow in clusters at the end of each branch.  Its flowers typically have five petals each.  Each flower may be 1-2 inches in diameter and is often sweet scented.  Its fruit is a brown, long (2-9 inches), narrow, pod-like structure with many small, downy seeds.

All parts of the plant are very poisonous. Do not use the wood for cooking or spearing food; it gives off poisonous fumes that can poison food.  Symptoms of poisoning include gastrointestinal and cardiac effects.  Individuals may experience nausea, vomiting, excessive salivation, abdominal pain, diarrhea, cramps, irregular heart rate, blurred vision, racing heart rate (which slows further on in the reaction), pale and cold extremities, drowsiness, low blood pressure, weakness, tremors and shaking of muscles, disorientation, dizziness, headache, seizures, collapse, coma, and death. Extremities may become pale and cold due to poor or irregular circulation.

Oleander sap can cause skin irritations and severe eye inflammation if the sap comes in contain with the eye.

If ingested, attempt to induce vomiting to reduce absorption of toxic compounds.  Charcoal may be ingested to absorb compounds.

Birds and rodents are relatively insensitive to oleander cardiac glycosides. Other mammals, however, such as dogs and humans, are relatively sensitive to the effects of cardiac glycosides and the clinical manifestations of “glycoside intoxication”. It is also hazardous for animals such as sheep, horses, cattle, and other grazing animals, with as little as 100 g being enough to kill an adult horse. Plant clippings are especially dangerous to horses, as they are sweet.

Drying plant materials does not eliminate the toxins. Many of the oleander relatives, such as the desert rose (Adenium obesum) found in East Africa, have similar leaves and flowers and are equally toxic.

Habitat and Distribution

This native of the Mediterranean area is now grown as an ornamental in tropical and temperate regions.  It grows natively around dry stream beds.

Oleander plant identification visual guide

Image Credits

Flowers and leaves of Nerium oleander pink red via Wikimedia Commons with usage type - GNU Free. June 2007
Plant, leaves, flowers, and bud of Nerium oleander via Wikimedia Commons with usage type - GNU Free
Nerium oleander leaves and pink flowers via Wikimedia Commons by Zeynel Cebeci with usage type - Creative Commons License. June 13, 2020
Nerium oleander bush in the wild via Wikimedia Commons by Zeynel Cebeci with usage type - Creative Commons License. June 7, 2020
White Nerium oleander flowers via Wikimedia Commons by George E. Koronaios with usage type - Creative Commons License. June 5, 2019
Pink Nerium oleander flower petals via Wikimedia Commons by Syrio with usage type - Creative Commons License. June 3, 2018
Pinkish white Nerium oleander stem, bud, and flower via Wikimedia Commons with usage type - Creative Commons License. March 19, 2012
Nerium oleander flower bunch via Wikimedia Commons with usage type - Creative Commons License. March 19, 20112
Nerium oleander pink flower via Wikimedia Commons by 白布飘扬 with usage type - Creative Commons License. March 19, 2012
Seeds of oleander (Nerium oleander) via Wikimedia Commons by Zeynel Cebeci with usage type - Creative Commons License. February 15, 2020
Oleander flower buds (Nerium oleander) via Wikimedia Commons by David E. Mead with usage type - Creative Commons License. September 1, 2016
Oleander bush in the wild via Wikimedia Commons by Zeynel Cebeci with usage type - Creative Commons License. June 13, 2020
White pink Nerium oleander flowers via Wikimedia Commons with usage type - Creative Commons License. October 12, 2020
White and yellow oleander flowers via Wikimedia Commons with usage type - Creative Commons License. May 2, 2022

Featured Image Credit

Nerium oleander leaves and pink flowers via Wikimedia Commons by Zeynel Cebeci with usage type - Creative Commons License. June 13, 2020
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