Willow bark comes from the bark of various species of willow trees, particularly the Salix genus. It has been used for centuries in traditional medicine due to its natural pain-relieving properties. The active ingredient in willow bark is salicin, which the body converts into salicylic acid, a compound similar to aspirin. In addition to pain relief, willow bark is also known for its anti-inflammatory and antioxidant effects. It is commonly used to alleviate headaches, muscle pain, and arthritis symptoms. However, individuals should consult a healthcare professional before using willow bark, especially if they are taking other medications.