Health Canada
Symbol of the Government of Canada
Drugs and Health Products

WILLOW BARK

Help on accessing alternative formats, such as Portable Document Format (PDF), Microsoft Word and PowerPoint (PPT) files, can be obtained in the alternate format help section.

This monograph is intended to serve as a guide to industry for the preparation of Product Licence Applications (PLAs) and labels for natural health product market authorization. It is not intended to be a comprehensive review of the medicinal ingredient.

Notes
  • Text in parentheses is additional optional information which can be included on the PLA and product label at the applicant's discretion.
  • The solidus (/) indicates that the terms and/or the statements are synonymous. Either term or statement may be selected by the applicant.

Date

October 18, 2013

NHPID Name

Willow Bark

Proper name(s)

Willow Bark (Bradley 1992; Blumenthal et al. 2000)

Common name(s)

Willow Bark (Bradley 1992; Blumenthal et al. 2000)

Source material(s)

  • Salix alba L. - Young branch bark (USDA 2007; Wichtl 2004; ESCOP 2003; Blumenthal et al. 2000)
  • Salix daphnoides Vill. - Young branch bark (USDA 2007; Wichtl 2004; ESCOP 2003; Blumenthal et al. 2000)
  • Salix x fragilis L. - Young branch bark (USDA 2007; Wichtl 2004; ESCOP 2003; Blumenthal et al. 2000)
  • Salix purpurea L. - Young branch bark (USDA 2007; Wichtl 2004; ESCOP 2003; Blumenthal et al. 2000)

Route(s) of administration

Oral

Dosage form(s)

  • The acceptable pharmaceutical dosage forms include, but are not limited to capsules, chewables (e.g. gummies, tablets), liquids, powders, strips or tablets.
  • This monograph is not intended to include foods or food-like dosage forms such as bars, chewing gums or beverages.

Use(s) or Purpose(s)

Statement(s) to the effect of
  • Used in Herbal Medicine for short-term relief of low back pain (EMEA 2009).
  • (Traditionally) used in Herbal Medicine for the relief of minor joint pain (due to osteoarthritis) (EMEA 2009, ESCOP 2003).
  • (Traditionally) used in Herbal Medicine to relieve fever associated with the common cold (EMEA 2009).
  • (Traditionally) used in Herbal Medicine to relieve headache pain (EMEA 2009).
Note
A claim for traditional use must include the term "Herbal Medicine".

Dose(s)

Statement(s) to the effect of

Subpopulation(s)

Adults (≥ 18 years)

Quantity(ies)

Dry, Powder, Decoction & Infusion + All Non-Standardized Extracts

3- 9 g dried bark per day in divided doses, not to exceed 3 g per dose (EMEA 2009; ESCOP 2003; Barnes et al. 2002; Blumenthal et al. 2000)

Standardized Extracts

45 to 240 mg total salicin per day in divided doses, not to exceed 120 mg salicin per dose (EMEA 2009; Wichtl 2004; ESCOP 2003; Barnes et al. 2002; Blumenthal et al. 2000) or 0.5-1% total salicin (after hydrolysis) (WHO 2009)

Duration of use

Statement(s) to the effect of

For prolonged use, consult a health care practitioner (EMEA 2009; Beer and Wegener 2008; Biegert et al. 2004; Chrubasik 2000).

Risk information

Statement(s) to the effect of

Caution(s) and warning(s)

  • If symptoms persist or worsen, consult a health care practitioner.
  • If you experience gastrointestinal symptoms such as nausea, vomiting, abdominal pain, dyspepsia, heartburn or diarrhea, discontinue use and consult a health care practitioner (Brinker 2010; Wichtl 2004, ESCOP 2003; McGuffin 2000; Blumenthal 2000; Barnes et al. 2002; EMEA 2009).
  • If you have asthma or peptic ulcer disease, consult a health care practitioner prior to use(EMEA 2009).
  • If you are taking anticoagulants or products containing acetylsalicylic acid (ASA) or other salicylates, consult a health care practitioner prior to use (EMEA 2009).

Contraindication(s)

  • If you are allergic to acetylsalicylic acid (ASA) or other salicylates, do not use this product (Brinker 2010; EMEA 2009; Wichtl 2004, ESCOP 2003; Barnes et al. 2002; Blumenthal et al. 2000).
  • If you are pregnant or breastfeeding, do not use this product (Brinker 2010; EMEA 2009; Wichtl 2004; ESCOP 2003; Barnes et al. 2002; Blumenthal et al. 2000).

Known adverse reaction(s)

No statement required.

Non-medicinal ingredients

Must be chosen from the current NHPD Natural Health Products Ingredients Database (NHPID) and must meet the limitations outlined in the database.

Storage conditions

No statement required.

Specifications

References cited

  • Barnes J, Anderson LA, Philipson JD. Herbal Medicines: A Guide for Healthcare Professionals. 2nd edition. London (GB): The Pharmaceutical Press; 2002.
  • Beer A.-M, Wegener T. Willow bark extract (Salicis cortex) for gonarthrosis and coxarthrosis- Results of a cohort study with a control group. Journal of Phytomedicine 2008; 15: 907-913.
  • Biegert C, Wagner I, Ludtke R, Kotter I, Lohmuller C, Gunaydin I, Taxis K, Heide L. Efficacy and safety of willow bark extract in the treatment of osteoarthritis and rheumatoid arthritis: results of 2 randomized double-blind controlled trials. Journal of Rheumatology 2004; 31 (11): 2121-2130.
  • Blumenthal M, Goldberg A, Brinckmann J, editors. Herbal Medicine: Expanded Commission E Monographs. Newton (MA): Integrative Medicine Communications; 2000.
  • Bradley PR, editor. British Herbal Compendium: A Handbook of Scientific Information on Widely Used Plant Drugs, Volume 1. Bournemouth (GB): British Herbal Medicine Association; 1992.
  • Barnes J, Anderson LA, Philipson JD. Herbal Medicines: A Guide for Healthcare Professionals. 2nd edition. London (GB): The Pharmaceutical Press; 2002.
  • Brinker F. Herb Contraindications and Drug Interactions, 3rd edition. Sandy (OR): Eclectic Medical Publications; 2010.
  • Chrubasik S, Eisenberg E, Balan E, Weinberger T, Luzzati R, Conradt C. Treatment of low back pain exacerbations with willow bark extract: a randomised double-blind study. The American Journal of Medicine. 2000; 109: 9-14.
  • EMEA 2009Next link will take you to another Web site European Medicines Agency. Community Monograph. London (GB): EMEA Committee on Herbal Medicinal Products (HMPC), 14 January 2009. [Accessed 2013-01-09].
  • ESCOP 2003: E/S/C/O/P Monographs: The Scientific Foundation for Herbal Medicinal Products. 2nd edition. Exeter (GB): ESCOP, the European Scientific Cooperative on Phytotherapy in collaboration with Georg Thieme Verlag and Thieme; 2003.
  • USDA 2007:Next link will take you to another Web site United States Department of Agriculture, Agricultural Research Service, National Genetic Resources Program. Germplasm Resources Information Network (GRIN). National Germplasm Resources Laboratory, Beltsville (MD). [Last updated 2007 May 29; Accessed 2013 October 1].
  • Wichtl M, editor. Herbal Drugs and Phytopharmaceuticals: A Handbook for Practice on a Scientific Basis. 3rd edition. Stuttgart (DE): Medpharm Scientific Publishers; 2004.
  • WHO 2009: World Health Organization. WHO Monographs on Selected Medicinal Plants, Volume 4. Geneva (CH): World Health Organization; 2009.