Coumarin Plant Poisoning Clinical Presentation

  • Author: Arasi Thangavelu, MD, FACEP, FAAEM; Chief Editor: Asim Tarabar, MD  more...
Updated: Mar 31, 2014


See the list below:

  • Elicit a history of exposure to medicinal hydroxycoumarins or rodenticides.
  • History may be difficult to obtain from patients who have ingested hydroxycoumarin products surreptitiously or with suicidal intent.
  • Ask the following questions to ascertain specific history:
    • Was ingestion a pharmaceutical or a long-acting rodenticide preparation?
    • Was ingestion intentional or unintentional? (Single unintentional ingestions of warfarin and warfarin-containing rodenticides usually are harmless; however, intentional and large unintentional ingestions of pharmaceutical-grade anticoagulants or rodenticides can produce life-threatening bleeding.)
    • How much was ingested?
    • When did the ingestion occur?
    • Was the ingestion a single acute ingestion or a chronic ingestion?


Bleeding diathesis does not occur until 24 hours postingestion. Continued re-evaluation for signs of coagulopathy is necessary.

Complications of excessive anticoagulation may occur. Initially, assessment of hemodynamic status and neurologic status are most important.

  • Excessive ecchymosis, gangrene, and skin necrosis
  • Purpura
  • Subconjunctival hemorrhage
  • Bleeding gums
  • Epistaxis
  • Menorrhagia
  • Gross hematuria
  • Hematomas
  • Compartment syndromes
  • Immediately life-threatening hemorrhage
    • Massive GI bleeding (eg, hematemesis, melena)
    • Intracranial hemorrhage
    • Upper airway compromise due to expanding hematoma


Warfarin anticoagulants and the anticoagulant rodenticides (Human toxicity from ingestion of plants and herbal medications is extremely rare.)

Contributor Information and Disclosures

Arasi Thangavelu, MD, FACEP, FAAEM Consulting Staff, Department of Emergency Medicine, Archbold Memorial Hospital

Arasi Thangavelu, MD, FACEP, FAAEM is a member of the following medical societies: American Academy of Emergency Medicine, Emergency Medicine Residents' Association, American College of Emergency Physicians

Disclosure: Nothing to disclose.


Lisandro Irizarry, MD, MPH, FACEP Chair, Department of Emergency Medicine, Wyckoff Heights Medical Center

Lisandro Irizarry, MD, MPH, FACEP is a member of the following medical societies: American Academy of Emergency Medicine, American College of Emergency Physicians, American College of Medical Toxicology, Society for Academic Emergency Medicine

Disclosure: Nothing to disclose.

Specialty Editor Board

John T VanDeVoort, PharmD Regional Director of Pharmacy, Sacred Heart and St Joseph's Hospitals

John T VanDeVoort, PharmD is a member of the following medical societies: American Society of Health-System Pharmacists

Disclosure: Nothing to disclose.

Chief Editor

Asim Tarabar, MD Assistant Professor, Director, Medical Toxicology, Department of Emergency Medicine, Yale University School of Medicine; Consulting Staff, Department of Emergency Medicine, Yale-New Haven Hospital

Disclosure: Nothing to disclose.

Additional Contributors

B Zane Horowitz, MD, FACMT Professor, Department of Emergency Medicine, Oregon Health and Sciences University School of Medicine; Medical Director, Oregon Poison Center; Medical Director, Alaska Poison Control System

B Zane Horowitz, MD, FACMT is a member of the following medical societies: American College of Medical Toxicology

Disclosure: Nothing to disclose.


Michael Hodgman, MD Assistant Clinical Professor of Medicine, Department of Emergency Medicine, Bassett Healthcare

Michael Hodgman, MD is a member of the following medical societies: American College of Medical Toxicology, American College of Physicians, Medical Society of the State of New York, and Wilderness Medical Society

Disclosure: Nothing to disclose.

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