When you are suffering from a fever, it is important to “break” the fever, which is often signaled by sweating. Willow is a powerful herb that has been in use for centuries that can actually increase the body temperature, thus promoting sweating. Once a fever has broken, the body can begin to heal and repair, and also attack the underlying infection with full force. There are a number of ways that willow can be used to treat yellow fever; you can brew a mild tea with willow leaves, prepare a decoction of the essential oils and active ingredients, or even draw a warm bath infused with willow leaves to enjoy the fever-breaking effects.