Poisonous oleander: recognising & treating symptoms


For me plants are some of the most exciting living beings, even though they live in slow motion. They have fascinating abilities and just so much potential! That's why I studied organic farming. However, since plants are rather thin on the ground in my city, I often spend time hiking in the nearby mountains at the weekend. In the future I would love to run a farm myself.

Favourite fruit: strawberries and gooseberries
Favourite vegetable: courgettes

As beautiful as its flowers look, the oleander is highly poisonous. Let us show you how to recognise and treat oleander poisoning in humans and animals.

Cat under a pink flowering oleander
All parts of the oleander contain substances that are toxic to animals and humans [Photo: Alexander Fadeev/ Shutterstock.com]

Oleander (Nerium oleander) should be grown with extreme caution. All parts of the plant contain substances toxic to humans. Nevertheless, oleander usually does not pose a danger to children or pets, as it tastes very bitter. However, if something should happen, you must absolutely and immediately take measures to prevent serious poisoning.

Is oleander poisonous?

Oleander is poisonous and the exact reason for this are the glycosides oleandrin and neandrin. The plant produces both substances as defense against predators, but they are also effective against humans. However, many plant toxins are also used in small doses as medicines – oleandrin for example, can have a calming and strengthening effect on the heart and can be used to treat eczema. However, treatment using oleandrin may only be carried out using approved ready-made medication from a pharmacy and under the supervision of a doctor!

Which parts of the oleander are poisonous?

The leaves, flowers, fruit and even the roots – all parts of the oleander are poisonous. Although widespread ornamental varieties have a slightly lower toxin content than wild varieties, but they should still be handled with care. Even the smoke from burning oleander is poisonous. For this reason, avoid burning any green waste from the plant; it is best to dispose of it in your household waste. The toxicity of oleander is about the same as that of lily of the valley (Convallaria majalis) and foxglove (Digitalis purpurea). However, although it is toxic and may even cause death in high doses, it is less dangerous than wolf’s bane (Aconitum) and autumn crocus (Colchicum autumnale). Since a lethal dose is far more than one leaf and the leaves of the oleander taste extremely bitter, a fatal outcome is very unlikely if consumed. However, symptoms of poisoning can occur, especially in children, even if a leaf is put in the mouth.

Signs of oleander posioning

Oleandrin is very efficient in the treatment of cardiac disorders. However, in higher doses it has the opposite effect and can become very dangerous. To prevent it from getting that far in the first place, you should contact a doctor immediately if symptoms are evident.

Symptoms of poisoning in children and adults

Poisoning with oleandrin and neandrin causes nausea and vomiting, as well as abdominal pain and diarrhoea. Blood circulation deteriorates, meaning that extremities such as hands and feet become pale and cold. Poisoning can also be recognised by enlarged pupils. If the dose is too high, it can because cardiac arrhythmia and paralysis of the heart and breathing. The consequences of this are a coma and in extreme cases, after two to three hours, death.

Note: Even skin contact with oleander sap can cause irritation. Therefore, wear protective gloves when pruning oleander.

Symptoms of poisoning in cats, dogs and other animals.

Animals generally display very similar symptoms of poisoning to children and adults: pupils become wider and extremities have poorer blood supply and become cold. Vomiting and diarrhoea are other symptoms.

A cat atop a wall under oleander
Oleander is also poisonous to our pets, but because of its bitter taste, it is unlikely to be consumed more widely [Photo: Katho Menden/ Shutterstock.com]

Treating oleander poisoning

If you have noticed that part of an oleander plant has been consumed by a person or an animal, immediately remove all plant residues from the mouth. Normally, these are immediately spat out again anyway due to the bitter taste. Afterwards, the affected person should drink a lot of fluids, preferably water. However, avoid choosing milk, as this only makes the absorption of the toxin into the body even stronger. The urge to vomit should also not be triggered. Contact a doctor immediately after these initial measures!

Procedures in the event of oleander poisoning:

  • Remove plant debris from the mouth
  • Drink plenty of water (but never milk!)
  • Contact a doctor immediately!
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