Willow Bark (sometimes known as Basket Willow, Bay Willow, or Corteza de Sauce) is found on the Willow tree and is removed for consumption after the tree is 2-3 years old. It has been used by ancient Greeks and Egyptians for centuries. The leaves and bark of the willow tree have been mentioned in ancient texts from Assyria, Sumer, and Egypt as a medicine for aches and fever. In ancient Greece, the physician Hippocrates discussed and wrote about its medicinal properties in the fifth century BC. Native Americans across the Americas relied on it as a staple for their medical treatments.