People have been using willow bark to ease inflammation, the cause of most aches and pains, for centuries. The bark of the white willow contains the chemical salicin, which is similar to the main ingredient in aspirin (Bayer).
Originally, people chewed the bark itself to relieve pain and fevers. Now willow bark is sold as a dried herb that you can brew like tea. It also comes as a liquid supplement or in capsule form. You can use willow bark to help relieve discomfort from headaches, low back pain, osteoarthritis (OA), and many other conditions.
However, willow bark comes with its own risk of side effects. It can cause stomach upset, may slow down your kidneys, and can prolong bleeding time, just like aspirin. It should only be used by adults. Similar to how aspirin taken in large quantities can be harmful for children, willow bark could be poisonous to children.