- The bark of the willow tree is the source of one of our most potent drugs, acetylsalicylic acid, known as aspirin. Natives used several varieties of the willow; they wove baskets with willow, used willow for pain and reducing fever; the gray willow (S. exigua) was called “Kosi tsube” by the Paiutes and the Shoshones. They used willow twigs with salt, steeped and drank for laxative. – Willow was one of the first herbs to be scientifically investigated. In the 19th century, the French chemist, Ler
