... White Willow Bark Extract: Appearance:Light brown fine powder Specification:Salicin(15%, 25%,50%) Test Method:HPLC White Willow Bark ExtractIndications and UsageWhite Willow Bark contains salicin, ... headaches and rheumatism and reducing fevers. Avoid white willow bark, which can irritate the stomach, if you ... .As with aspirin products, never give white willow bark to children or teenagers under age 16 ...