Willow bark
Also listed as: Crack willow; European willow; Liu-zhi; Purple willow;
Pussy willow; Salix alba; Salix nigra; Wheeping willow; White willow

Overview
Plant Description
Medicinal Uses and Indications
Dosage and Administration
Precautions
Interactions and Depletions
Supporting Research

Overview
The use of willow bark dates back to the time of Hippocrates (400 BC)
when patients were advised to chew on the bark to reduce fever and
inflammation. Willow bark has been used throughout the centuries in
China and Europe, and continues to be used today for the treatment of
pain (particularly low back pain and osteoarthritis), headache, and
inflammatory conditions such as bursitis and tendinitis. The bark of
white willow contains salicin, which is a chemical similar to aspirin
(acetylsalicylic acid) and is thought to be responsible for the pain-
relieving and anti-inflammatory effects of the herb. In fact, in the
1800s, salicin was used to develop aspirin. White willow appears to be
slower than aspirin to achieve any effects, but those effects may last
longer.

Plant Description
The willow family includes a number of different species of deciduous
trees and shrubs native to Europe, Asia, and some parts of North
America. Some of the more commonly known are white willow/European
willow ( Salix alba ), black willow/pussy willow ( Salix nigra ),
crack willow ( Salix fragilis ), purple willow ( Salix purpurea ), and
weeping willow ( Salix babylonica ). The willow bark sold in Europe
and the United States usually includes a combination of the bark from
white, purple, and crack willows.

Medicinal Uses and Indications
Willow bark is used to ease pain and reduce inflammation, and there is
good evidence that it is effective as an analgesic and anti-
inflammatory. Researchers believe that the chemical salicin, found in
willow bark, is responsible for these effects. However, studies have
identified several other components of willow bark which have
antioxidant, fever-reducing, antiseptic, and immune-boosting
properties. Some studies have shown willow is as effective as aspirin
for reducing pain and inflammation (but not fever), and at a much
lower dose. Researchers theorize that may be due to the other
compounds in the herb. More research is needed.

Treatment
Studies suggest that willow bark may be useful for the following
conditions:

Headache

Willow bark has been shown to relieve headaches and there is some
evidence that it is less likely to cause the same gastrointestinal
side effects that other pain relievers, such as ibuprofen and other
nonsteroidal anti-inflammatory drugs, do. However, studies have not
shown this conclusively, and people who are prone to stomach upset may
want to avoid willow bark. Large-scale studies are needed to fully
determine the safety and effectiveness of willow bark for chronic or
recurrent headaches.

Low back pain

Willow bark appears to be effective for back pain. In a well-designed
study of nearly 200 people with low back pain, those who received
willow bark experienced a significant improvement in pain compared to
those who received placebo. People who received higher doses of willow
bark (240 mg salicin) had more significant pain relief than those who
received low doses (120 mg salicin).

Osteoarthritis

Several studies have shown that willow is more effective at reducing
pain from osteoarthritis than placebo. In a small study of people with
osteoarthritis of the neck or lower back, those who received willow
bark experienced significant improvement in symptoms compared to those
who received placebo. A similar study of 78 patients hospitalized with
osteoarthritis of the knee or hip joint found that patients who
received willow bark experienced significant pain relief compared to
those who received placebo.

Other uses

Some professional herbalists may recommend willow bark for the
following conditions, although at present, no scientific studies have
supported these uses:

Menstrual cramps
Fever
Flu
Tendonitis
Bursitis

Dosage and Administration

Pediatric
Because of the danger of developing Reye syndrome (a rare but serious
illness associated with the use of aspirin in children), children
under the age of 16 should not be given willow bark.

Adult
General dosing guidelines for willow bark are as follows:

Dried herb (used to make tea): boil 1 - 2 tsp of dried bark in 8 oz of
water and simmer for 10 - 15 minutes; let steep for ½ hour; drink 3 -
4 cups daily
Powdered herb (available in capsules) or liquid: 60 - 240 mg of
standardized salicin per day; talk to your doctor before taking a
higher dose
Tincture (1:5, 30% alcohol): 4 - 6 mL three times per day

Precautions
Because willow bark contains salicin, people who are allergic or
sensitive to salicylates (such as aspirin) should not use willow bark.
Some researchers suggest that people with asthma, diabetes, gout,
gastritis, hemophilia, and stomach ulcers should also avoid willow
bark. If you have any of these conditions, take nonsteroidal anti-
inflammatory drugs (NSAIDs) regularly or blood-thinning medication, be
sure to consult your health care provider before taking willow bark.
Willow bark should not given to children under the age of 16.

Side Effects
Side effects tend to be mild. However, gastrointestinal irritation and
ulcers are potentially associated with all compounds containing
salicylates. Overdoses of willow bark may cause skin rash, stomach
inflammation/irritation, nausea, vomiting, kidney inflammation, and
tinnitus (ringing in the ears).

Pregnancy and Breastfeeding
Salicylates are not recommended during pregnancy, so pregnant and
breastfeeding women should not take willow bark.

Interactions and Depletions
Because willow bark contains salicylates, it has the potential to
interact with a number of drugs and herbs. Talk to your doctor before
taking willow bark if you take any other medications, herbs, or
supplements.

Willow bark may interact with any of the following:

Anticoagulants (blood-thinning medications) -- Willow bark may
strengthen the effects of drugs and herbs with blood-thinning
properties.

Beta blockers -- including Atenolol (Tenormin), Metoprolol (Lopressor,
Toprol-XL), Propranolol (Inderal, Inderal LA). Willow bark may reduce
the effectiveness of these drugs.

Diuretics (water pills) -- Willow bark may reduce the effectiveness of
these drugs.

Nonsteroidal anti-inflammatory drugs -- including ibuprofen (Advil,
Motrin) and naproxen (Aleve). Taking willow bark with these drugs may
increase risk of stomach bleeding.

Methotrexate and phenytoin (Dilantin) -- Willow may increase levels of
these drugs in the body, resulting in toxic levels.

Supporting Research
Bisset NG. Herbal Drugs and Phytopharmaceuticals . Stuttgart, Germany:
Medpharm Scientific Publishers; 1994:437-439.

Blumenthal M. The Complete German Commission E Monographs . Austin,
Tex: American Botanical Council. Boston: Integrative Medicine
Communications; 1998.

Bjornsson, T. 1475. An Icelandic medical manuscript tr. by Larsen
1931, cited in Erichsen-Brown C. Use of Plants for the Past 500
Years . Toronto, Canada: Breezy Creek Press; 1979.

Bradley PR. British Herbal Compendium. Volume 1. London: British
Herbal Medicine Association; 1997.

Chrubasik S. Pain therapy using herbal medicines [abstract].
Gynakologe . 2000;33(1):59-64.

Chrubasik S, Eisenburg E, Balan E, et al. Treatment of low back pain
exacerbations with willow bark extract: a randomized double blind
study. Am J Med . 2000;109:9-14.

Ernst E, Chrubasik S. Phyto-anti-inflammatories. A systematic review
of randomized, placebo-controlled, double-blind trials. Rheum Dis Clin
North Am . 2000;26(1):13-27.

Foster S, Duke JA. A Field Guide to Medicinal Plants and Herbs of the
Eastern and Central US . Boston, Mass: Houghton Mifflin;
2000:321-323.

Gruenwald J, Brendler BA, Christof J, et al. PDR for Herbal
Medicines . Montvale, NJ: Medical Economics; 1999:1111-1112.

Heck AM, DeWitt BA, Lukes AL. Potential interactions between
alternative therapies and warfarin. Am J Health Syst Pharm .
2000;57(13):1221-1227.

Hoffmann D. Therapeutic Herbalism . Santa Cruz,Calif: Therapeutic
Herbalism Press; 2000.

Hsu Hong-Yen, Chen Yuh-Pan. Oriental Materia Medica: A Concise Guide .
Long Beach Calif: Oriental Healing Arts Institute; 1986.

Kuhn MA, Winston D. Herbal Therapy and Supplements . Philadelphia, Pa:
Lippincott; 2001.

McGuffin M, Hobbs C, Upton R, et al, eds. American Herbal Products
Association's Botanical Safety Handbook . Boca Raton, Fla: CRC Press;
1997:101.

Newall CA, Anderson LA, Phillipson JD. Herbal Medicines: A Guide for
Health-Care Professionals . London, England: The Pharmaceutical Press;
1996:268-270.

Schilcher H. Phytotherapy in Paediatrics: Handbook for Physicians and
Pharmacists. Stuttgart, Germany: Medpharm; 1997.

Schmid B, Ludtke R, Selbmann HK, et al. Efficacy and tolerability of a
standardized willow bark extract in patients with osteoarthritis:
randomized placebo-controlled, double blind clinical trial. Phytother
Res. 2001 Jun;15(4):344-50.

Setty AR, Sigal LH. Herbal medications commonly used in the practice
of rheumatology: mechanisms of action, efficacy, and side effects.
Semin Arthritis Rheum. 2005 Jun;34(6):773-84.

Weiss RF; Meuss AR, trans. Herbal Medicine. Beaconsfield, England:
Beaconsfield Publishers; 1994:302-303.

Review Date: 2/13/2007
Reviewed By: Steven D. Ehrlich, N.M.D., private practice specializing
in complementary and alternative medicine, Phoenix, AZ. Review
provided by VeriMed Healthcare Network.

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