The use of willow bark dates back thousands of years, 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). In combination with the herb's powerful anti-inflammatory plant compounds (called flavonoids), salicin 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 bring pain relief more slowly than aspirin, but its effects may last longer.
The willow family includes a number of different species of trees and shrubs native to Europe, Asia, and some parts of North America. Some of the more commonly known species 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). Not all willow species accumulate a therapeutically sufficient amount of salicin. In one study, the amount of salicin after 1 and 2 year growth in autumn and spring ranged from 0.08 - 12.6%. The willow bark sold in Europe and the United States usually includes a combination of the bark from white, purple, and crack willows.
Willow bark is used to ease pain and reduce inflammation. Researchers believe that the chemical salicin, found in willow bark, is responsible for these effects. However, studies show several other components of willow bark, including plant chemicals called polyphenols and flavonoids, have antioxidant, fever reducing, antiseptic, and immune boosting properties. Some studies show willow is as effective as aspirin for reducing pain and inflammation (but not fever), and at a much lower dose. Scientists think that may be due to other compounds in the herb. More research is needed
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