Knowing plants and there medicinal properties is an excellent skill to have. For instance willow bark acts a lot like aspirin, so it can be used to relieve pain and even fevers.
You can use the bark from several varieties of the willow tree, including white willow, european willow, black willow, pussy willow, crack willow, purple willow, and others. So give the video below a watch and learn how to make aspirin from willow bark.