Evidence Level
White willow bark has been used for pain relief for over 3,500 years and was the inspiration for aspirin development in the 1890s. The key clinical trial by Chrubasik et al. (2000, n=210) found 240mg salicin daily superior to placebo for acute low back pain, with a separate trial showing comparable efficacy to rofecoxib. Schmid et al. (2001, n=78) confirmed benefit for hip/knee OA. Notably, willow bark appears gentler on the stomach than aspirin because salicin is converted to salicylic acid after intestinal absorption, bypassing direct gastric irritation. However, it should still be avoided in aspirin-sensitive individuals. The presence of additional polyphenols may explain why willow bark has broader anti-inflammatory effects than the equivalent salicin dose alone would predict.