Educational information, not medical advice — ask your doctor or midwife.
Willow bark extract comes from the inner bark of several willow tree species, most commonly white willow (Salix alba). It has been used as a natural pain reliever and fever reducer for thousands of years across ancient Egypt, Greece, Rome, and traditional Chinese medicine. The active compound salicin is converted by the body into salicylic acid, which is the same family of compounds that gave rise to aspirin — making willow bark one of humanity's oldest documented medicines.
When you take willow bark, gut bacteria and liver enzymes convert salicin into salicylic acid, which reduces the production of prostaglandins — the chemicals your body releases that cause pain, swelling, and fever. Unlike aspirin (acetylsalicylic acid), the conversion happens gradually, which may explain why it tends to be gentler on the stomach and longer-lasting. The flavonoids and polyphenols in the bark also contribute anti-inflammatory and antioxidant effects beyond what salicin alone provides.
Standardized capsules and tablets are the most reliable form for therapeutic dosing — look for products standardized to at least 15% salicin. Tinctures and liquid extracts are fast-absorbing but harder to dose precisely. Bark teas are traditional but contain lower and less predictable amounts of salicin. Topical creams are available for localized joint or muscle pain but have weaker evidence than oral forms.
Willow bark is one of the oldest documented medicines in human history. Ancient Egyptians referenced chewing willow leaves for pain and fever in the Ebers Papyrus (~1550 BCE). Hippocrates prescribed willow bark tea for fever and labor pain in ancient Greece. Its widespread use across European folk medicine eventually led 19th-century chemists to isolate salicin in 1828 (Leroux) and then synthesize acetylsalicylic acid (aspirin) in 1897 — making willow bark the direct ancestor of the world's most widely used drug.
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