Aspirin toxicity willow tree acmt

Which medication can be derived from the bark of the pictured tree?

  1. Aspirin
  2. Atropine
  3. Colchicine
  4. Quinine

1. Aspirin


The photo shows a weeping willow, a member of the Salix genus of trees. Willow tree bark contains salicin from which aspirin (acetylsalicylic acid) can be derived.

For over 3500 years, willow bark has been used as a traditional medicine to treat fevers and pain [1]. The active compound, salicin, is metabolized to salicylic acid in the body providing analgesic and antipyretic effects [2]. In 1897, Dr. Felix Hoffman modified salicylic acid and created acetylsalicylic acid (aspirin), now the most-used drug in the world due to its role in preventing cardiovascular and cerebrovascular disease [1].

How can people become poisoned with willow bark?

  • Willow tree bark extract has been used as an herbal supplement for chronic lower back pain, joint pain, osteoarthritis, sports performance, and weight loss [3].
  • Willow tree bark supplements are available as tablets, tinctures, powders, or tea.
  • Cases of toxicity have been reported following ingestion of supplements as well as ingestion of willow bark tea [4,5].
  • However, most adverse reactions from willow bark supplements have been associated with people who have aspirin allergies, with numerous cases of anaphylaxis [6].

How does willow bark toxicity present? [7]

  • Toxicity from salicin mirrors toxicity from aspirin (salicylism) in its clinical presentation.
  • One study shows that ingestion of 240 mg of salicin in willow bark tablets produced salicylate levels equivalent to 87 mg of acetylsalicylic acid, therefore serum salicylate levels will be detectable following ingestion [8].
  • Salicylate has a direct effect on the respiratory center of the medulla causing tachypnea.
  • Tinnitus, nausea, vomiting, and abdominal pain are common.
  • With severe toxicity, patients can have altered mental status, seizures, hyperthermia, and pulmonary edema.
  • Further information on the diagnosis and treatment of salicylate toxicity

Bedside Pearls

  • Willow tree bark (Salix genus) contains salicin, which is metabolized in the body to salicylic acid.
  • Ingestion of willow bark supplements can cause salicylism.
  • Patients who have an aspirin allergy should avoid willow tree bark supplements, extracts, or teas.


  1. Desborough MJR, Keeling DM. The Aspirin Story – from Willow to Wonder Drug. British Journal of Haematology. 2017;177(5):674-683. PMID: 28106908.
  2. Schmid B, Kötter I, Heide L. Pharmacokinetics of salicin after oral administration of a standardised willow bark extract. European Journal of Clinical Pharmacology. 2001;57(5):387-391. PMID: 11599656.
  3. Shara M, Stohs SJ. Efficacy and Safety of White Willow Bark (Salix alba) Extracts. Phytotherapy Research. 2015;29(8):1112-1116. PMID: 25997859.
  4. Srivali N, Cheungpasitporn W, Chongnarungsin D, Edmonds LC. White willow bark induced acute respiratory distress syndrome. N Am J Med Sci. 2013 May;5(5):330. PMID: 23814765.
  5. Kuzak N, Brubacher JR, Kennedy JR. Reversal of salicylate-induced euglycemic delirium with dextrose. Clinical Toxicology. 2007;45(5):526-529. PMID: 17503260.
  6. Oketch-Rabah HA, Marles RJ, Jordan SA, Low Dog T. United States Pharmacopeia Safety Review of Willow Bark. Planta Medica. 2019;85(16):1192-1202. PMID: 31604354.
  7. Palmer BF, Clegg DJ. Salicylate Toxicity. New England Journal of Medicine. 2020;382(26):2544-2555. PMID: 32579814.
  8. Schmid B, Kötter I, Heide L. Pharmacokinetics of salicin after oral administration of a standardised willow bark extract. European Journal of Clinical Pharmacology. 2001;57(5):387-391. PMID: 11599656.
Joanne Alonso, MD

Joanne Alonso, MD

Emergency Medicine Resident
New York City Health Hospitals/South Brooklyn Health
Joanne Alonso, MD

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Bhojnarine Seeram, MD

Bhojnarine Seeram, MD

Emergency Medicine Faculty
New York City Health Hospitals/South Brooklyn Health
Bhojnarine Seeram, MD

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