Bovis ISSN 2398-2993

Oleander poisoning

Synonym(s): Nerium oleander toxicity

Contributor(s): Nicola Bates , Lisa Whitfield

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  • Cause: ingestion of oleander (Nerium oleander).
  • Signs: anorexia, depression, signs of abdominal pain, weakness and arrhythmias.
  • Diagnosis: based on history of exposure, clinical signs and post-mortem findings.
  • Treatment: supportive.
  • Prognosis: poor.



  • Green leaves appear to be unpalatable unless mixed with feed.
  • Circumstances include:
    • Access to pasture bordered by oleander plants .
    • Access to cuttings of oleander.
    • Ingestion of leaves mixed with fodder.

Predisposing factors


  • Access to plants.
  • Lack of or inability to access other forage.


  • All parts of the plant are toxic, including the dried leaves.
  • Oleander contains a complex mixture of cardiac glycosides, mainly oleandrin, which are potent cardiac toxins.
  • Cardiac glycosides interfere with the cellular membrane sodium-potassium (Na+ -K+ ATPase enzyme system) pump resulting in depletion of intracellular potassium and an increase in serum potassium. This causes irregular heart activity, and eventual complete block of cardiac conduction.


  • Signs generally start within 6 hours. 
  • Death may occur rapidly (within a few hours) or up to 48 hours after ingestion.
  • Recovery may take several days.


  • Oleander is widely cultivated.
  • Poisoning can occur wherever oleander plants are grown.


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Further Reading


Refereed Papers

  • Recent references from PubMed and VetMedResource.
  • Varga A, Puschner B (2012) Retrospective study of cattle poisonings in California: recognition, diagnosis and treatment. Veterinary Medicine: Research and Reports 3, 111-127. 
  • Langford S D & Boor P J (1996) Oleander toxicity: an examination of human and animal toxic exposures. Toxicology 109, 1-13 PubMed.
  • Galey F D, Holstege D M, Plumlee K H, Tor E, Johnson B, Anderson M L, Blanchard P C & Brown F (1996) Diagnosis of oleander poisoning in livestock. Journal of Veterinary Diagnostic Investigation 8, 358-364 PubMed.
  • Oryan A, Maham M, Rezakhani A & Maleki M (1996) Morphological studies on experimental oleander poisoning in cattle. Journal of Veterinary Medicine A 43 (10), 625-34 PubMed.
  • Rezakhani A & Maham M (1992) Oleander poisoning in cattle of the Fars Province, Iran. Veterinary and Human Toxicology 34, 549 PubMed.
  • Mahin L, Marzou A & Huart A (1984) A case report of Nerium oleander poisoning in cattle. Veterinary and Human Toxicology 26, 303-304 PubMed.
  • Liu S K (1957) The pathology of oleander poisoning in cattle. Memoirs of the College of Agriculture; National Taiwan University 5, 75-82.
  • Soto-Blanco B, Fontenele-Neto J D, Silva D M, Reis P F & Nobrega J E (2006) Acute cattle intoxication from Nerium oleander pods. Tropical Animal Health and Production 38 (6), 451-4 PubMed.
  • Vermunt J (1987) Oleander - decorative and very poisonous. New Zealand Veterinary Journal 35, 138-139 PubMed.
  • Falciola C, Davanzo F, Rivolta M, Molino L, Colombo ML (2015) Nerium oleander: case report of a severe poisoning case involving numerous cows [abstract]. Clin Toxicol 53(7), 753.

Other sources of information

  • EMA (2015) CVMP assessment report regarding the request for an opinion under Article 30(3) of Regulation (EC) No. 726/2004 in relation to the potential risk for the consumer resulting from the use of lidocaine in food producing species. EMA/CVMP/118717/2015. Available from
  • Burrows G E & Tyrl R J (2013) Toxic Plants of North America. 2nd edn. Wiley Blackwell, Ames, Iowa.
  • Sakha M & Rezekhani A (2002) Treatment of oleander poisoning with V285 [abstract]. XXII World Buiatrics Congress, Hanover 18-23 August.
  • Cooper M R & Johnson A W (1998) Poisonous Plants and Fungi in Britain. 2nd edn. The Stationery Office, London.
  • Galey F D, Holstege D M, Johnson B J & Siemens L (1998) Toxicity and diagnosis of oleander (Nerium oleander) poisoning in livestock. In: Toxic Plants and Other Natural Toxicants. Eds: Garland T, Barr A C, Betz J M, Reagor J C, Bailey E M Jr. CAB International: Wallingford, UK. pp 215-219.
  • Rezakhani A & Maham M (1994) Cardiac manifestations of oleander poisoning in cattle and donkeys. In: Plant-associated Toxins: Agricultural, Phytochemical and Ecological Aspects. Eds: Colegate S M, Dorling P R, Allen J G, Huxtable C R & Panter K E. CAB International: Wallingford, UK. pp 534-537.