Coumarin Plant Poisoning Clinical Presentation

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