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.)