There are debates as to the exact identity of some of the Four Species which we use on Sukkot, for instance the “bough of a leafy tree”, which Jewish tradition identifies with the hadas or myrtle. Like others of the Four Species, it is said to have benefits for one’s health: a person who drinks tea made from hadas leaves is said to have a greater likelihood of long life.
There is no debate about what is meant by the willows or aravot. In Israel they grow along the streams and are easy to obtain, though in the Diaspora they sometimes need to be imported at considerable cost. The willows have a number of additional properties, including a medicinal use. They are said to be a good way of treating fever.
Some element in the willow leaves can combine with stomach acids to produce aspirin, so not only does the willow tree have a religious and symbolic role but can be said to be good for you.