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Nerium
Toxic🐾Oleander · (Nerium oleander)
Dogbane family (Apocynaceae)
Description
With its leathery evergreen leaves and clusters of pink to white flowers, oleander graces countless Mediterranean gardens and container plantings — and is at the same time one of Europe's most poisonous ornamentals. All parts, which flower between June and September, contain cardiac-active cardenolide glycosides, chiefly oleandrin, alongside neriin, adynerin and odoroside. Historically, heavily diluted leaf preparations were used externally and as a circulatory tincture in folk medicine, a use no longer recommended today given the poisoning risk. A single leaf can already be dangerous for a child, and even the water from a vase holding oleander twigs is toxic. Oleander branches must never be used as grill skewers — fatal poisonings are documented. Symptoms range from nausea and vomiting to dangerous heart rhythm disturbances. In suspected poisoning, emergency services should be contacted immediately; a specific antidote exists in the form of digitalis-specific antibody fragments.
🌿 Risk of confusion — read before wild-harvesting!
NEVER use oleander twigs as grill skewers — fatal picnic poisonings are documented.
External use only!
This plant must NOT be taken internally. Use only as compress, salve, or bath.
CONTRAINDICATED during pregnancy
Cardenolides cross the placental barrier and can trigger fetal arrhythmias and abortion. Any oral or large-area dermal application during pregnancy is strictly contraindicated.
CONTRAINDICATED during breastfeeding
Cardiac glycosides may pass into breast milk and induce cardiotoxic effects (bradycardia, AV block) in the infant. Lactation: strictly contraindicated.
CONTRAINDICATED for children
Children are particularly at risk due to low body mass and sensitive cardiac physiology — even a single leaf or a few seeds can be lethal. Oleander potted plants on balcony and terrace must be kept out of reach of children. Swallowed flowers or leaves: IMMEDIATELY call poison control.
Critical drug interactions with:
Herzglykoside (Digoxin, Digitoxin, Strophanthin, Convallaria-Glykoside) · Kaliumverlust-Diuretika (Thiazide, Schleifendiuretika wie Furosemid) · Intravenöses Calcium / Calcium-Salze · Beta-Blocker und Calciumkanal-Blocker (Verapamil, Diltiazem)
Folk medicinal external use of oleander leaf decoctions for scabies and parasitic skin infestation in the Mediterranean region and in India. Treatment of leprous skin lesions with root-bark oil is also documented in the Ayurvedic tradition. No longer recommended today due to strong skin irritation and percutaneous glycoside absorption through damaged skin.
Preparation & dosage
Indian Ayurvedic application of oleander root paste on genital ulcers and skin sores. Root-bark oil is also applied to scaly skin diseases and leprosy-related lesions. Despite traditional spread, this application is considered dangerous today due to percutaneous toxicity.
Preparation & dosage
Sources: [3]
Historical documentation only — do NOT use
These internal applications are historically documented. This plant is highly toxic — self-treatment can cause severe poisoning or death. For documentation only, explicitly NOT a recommendation.
Historical pharmaceutical use of standardised oleander leaf extracts (Folia Nerii) as a cardiac glycoside source in heart failure and dropsy — analogous to Digitalis purpurea. Mechanism: inhibition of cardiac Na+/K+-ATPase by oleandrin and related cardenolides, resulting in a positive inotropic effect. Obsolete today because digoxin and digitoxin are more standardised and more safely dosable; the therapeutic window of oleander extracts is extremely narrow.
Preparation & dosage
Homeopathic use of Nerium oleander (mother tincture, D2–D30) for cardiac weakness, arrhythmia and ascites in classical homeopathy. In high dilutions (from D6 onwards) preparations are considered safe because no pharmacologically active glycoside amount remains. Mother tincture and low potencies remain highly toxic.
Preparation & dosage
Ancient and medieval use as an alleged antidote for snake bites (mixed with rue, taken orally) — already mentioned by Pliny the Elder and Dioscorides. According to current knowledge this application is toxicologically counterproductive and additively dangerous.
Preparation & dosage
Sources: [1]
Investigation of oleandrin and oleander extracts (e.g. Anvirzel, PBI-05204) as experimental cancer and antiviral therapy in clinical trials. Results have been negative so far: the US FDA rejected an application for oleandrin as a dietary supplement in 2020; clinical efficacy is not established. Use outside controlled trials is dangerous.
Preparation & dosage
⚠ External use only
EXTREMELY TOXIC — ALL PLANT PARTS. Nerium oleander is among the most poisonous ornamentals in European gardens and on balconies. All parts (leaves, flowers, seeds, wood, roots, latex) contain cardenolide cardiac glycosides (oleandrin, neriin, adynerin, oleandrigenin, odoroside). A single leaf can be lethal for children; about 100 g of leaves are sufficient to kill a horse. Even the vase water of oleander twigs is toxic. NEVER use oleander twigs as grill skewers — fatal picnic poisonings are documented. Poisoning symptoms: nausea, vomiting, bloody diarrhoea, abdominal pain, bradycardia, AV block, hyperkalaemia, visual disturbances (xanthopsia), ventricular fibrillation, cardiac arrest. In suspected poisoning: IMMEDIATELY call emergency services and poison control. Antidote: digitalis-specific antibody fragments (Digifab) — also effective against oleandrin. No self-medication. No lay use. ASPCA classification (accessed 2026-08-10): toxic to dogs and cats.
Cardenolides cross the placental barrier and can trigger fetal arrhythmias and abortion. Any oral or large-area dermal application during pregnancy is strictly contraindicated.
Cardiac glycosides may pass into breast milk and induce cardiotoxic effects (bradycardia, AV block) in the infant. Lactation: strictly contraindicated.
Children are particularly at risk due to low body mass and sensitive cardiac physiology — even a single leaf or a few seeds can be lethal. Oleander potted plants on balcony and terrace must be kept out of reach of children. Swallowed flowers or leaves: IMMEDIATELY call poison control.
Drug interactions
Herzglykoside (Digoxin, Digitoxin, Strophanthin, Convallaria-Glykoside)
Additive inhibition of Na+/K+-ATPase and additive cardiac inotropy — cumulative toxicity with risk of AV block, ventricular arrhythmias and cardiac arrest. Concurrent use must be absolutely avoided.
Kaliumverlust-Diuretika (Thiazide, Schleifendiuretika wie Furosemid)
Diuretic-induced hypokalaemia substantially increases cardiac glycoside sensitivity of myocardial cells — poisoning possible at otherwise tolerated doses.
Intravenöses Calcium / Calcium-Salze
Intravenous calcium during cardiac glycoside poisoning is classically contraindicated (stone heart phenomenon): cardenolides block Na+/K+-ATPase and intracellular calcium rises; additional IV calcium may precipitate tetanic contracture and cardiac arrest.
Beta-Blocker und Calciumkanal-Blocker (Verapamil, Diltiazem)
Additive negative chronotropic and dromotropic effects at the sinus and AV node intensify glycoside-induced bradycardia and AV block risk.
QT-Zeit-verlängernde Medikamente (Antiarrhythmika Klasse Ia/III, Makrolide, Fluorchinolone, Antipsychotika)
Cardenolides can secondarily affect the QT interval; in combination, the risk of torsade de pointes and ventricular arrhythmias rises markedly.
Systemische Kortikosteroide und Laxanzien (chronisch)
Cause potassium depletion and thereby increased sensitivity to cardenolides — analogous to diuretics.
Contraindications
- Concurrent therapy with digitalis glycosides (digoxin, digitoxin) — additive, often fatal cardiotoxicity
- Hypokalaemia (e.g. under loop diuretics) — drastically increased cardiac glycoside sensitivity
- AV block grade II and III — prolongation of AV conduction by cardenolides
- Wolff-Parkinson-White syndrome and other accessory conduction pathways
- Renal insufficiency — delayed elimination of glycosides, risk of accumulation
- Hypertrophic obstructive cardiomyopathy (HOCM)
- Hypercalcaemia — increased glycoside toxicity through elevated intracellular calcium concentration
- Pregnancy, lactation and children under 18 years (see above)
Harvested part: all plant parts
- Time of day:
- Morning hours on dry summer days — highest cardenolide content in fully mature leaves
- Drying:
- Dry leaves in shade at 35–45 °C. PROTECTIVE GLOVES MANDATORY — latex is skin-irritating and percutaneously absorbed; avoid aerosol exposure when cutting. Store dried material in containers clearly labelled as TOXIC, out of reach of children and pets.
- Time of day:
- Morning after dew has dried, in full bloom
- Drying:
- Lay flowers flat and dry at max. 35 °C in shade; cultivar colour and cardenolide content remain stable. Wear protective gloves — pollen and nectar also contain glycosides.
- OleandrinGlycosideContent: 0.08-0.4 %
Main cardenolide of oleander leaves; competitive inhibitor of cardiac Na+/K+-ATPase; positive inotropic like digoxin but with a substantially narrower therapeutic window. LD50 (cat, i.v.) approx. 0.248 mg/kg; LD50 (animals general) approx. 0.5 mg/kg. Investigated in experimental cancer preparations Anvirzel and PBI-05204 — without clinical benefit so far.
- Oleandrigenin (Aglykon)GlycosideContent: Spuren
Deglycosylated aglycone of oleandrin; formed by metabolic breakdown and enzymatic hydrolysis; also pharmacologically cardioactive but with lower tissue affinity than the glycoside.
- NeriinGlycosideContent: nicht quantifiziert
Cardenolide glycoside of the Apocynaceae; contributes to overall oleander toxicity; pharmacologically related to oleandrin, action on Na+/K+-ATPase. Described in older pharmaceutical literature as 'nerein'.
- AdynerinGlycosideContent: nicht quantifiziert
Cardenolide glycoside detected in oleander leaves and bark; contributes additively to cardiotoxicity; lower affinity for Na+/K+-ATPase than oleandrin.
- Odoroside (Odorosid H)GlycosideContent: Spuren
Digitoxigenin glycoside with cardenolide structure; documented at Wikipedia level as a constituent of Nerium oleander; less studied than oleandrin but also cardiotoxic.
- AdigosideGlycosideContent: Spuren
Further cardenolide glycoside of oleander; component of the glycoside spectrum in leaves and bark; pharmacologically of subordinate importance.
- NeritalosideGlycosideContent: Spuren
Cardenolide glycoside related to oleandrin and detected in oleander leaf extracts; contributes to the glycoside pool of the plant material.
- Triterpene und Pregnan-GlykosideOtherContent: nicht quantifiziert
Accompanying steroids and triterpenes (ursolic acid, oleanolic acid, pregnane derivatives); pharmacologically subordinate to cardenolides, but routinely detected in phytochemical analyses.
- [5]MonographASPCA Animal Poison Control — Oleander (Nerium oleander)(accessed: 2026-08-10)
- [6]MonographCliniTox Giftpflanzen — Nerium oleander L.: sehr stark giftig +++ (Institut für Veterinärpharmakologie und -toxikologie, Universität Zürich)(accessed: 2026-08-10)
- [3]BookPlants For A Future — Nerium oleander(accessed: 2026-05-26)
- [1]WikipediaNerium oleander — Wikipedia (EN)(accessed: 2026-05-26)
- [2]WikipediaOleandrin — Wikipedia (EN)(accessed: 2026-05-26)
- [4]WikidataNerium oleander — Wikidata Q155833(accessed: 2026-05-26)