Willow bark has been used for centuries as a natural pain reliever. It contains salicin, which was later synthesized and is the active ingredient in aspirin. It’s reputed to relieve pain without the stomach upset chemical aspirin causes, and it’s easier on the liver too.
All willow species contain some amount of salicin, so it’s easy to find a tree in your area for making natural aspirin.
There are more than 300 species of willow, and each one is slightly different. They all contain salicin in varying amounts, as the family name Salicaceae suggests.
Read more here: How to Make Willow Bark Aspirin (practicalselfreliance.com)