Black Walnut Hulls come from the immature fruit of the Black Walnut Tree (Juglans nigra).&ampnbsp;&ampnbsp;References to the use of Black Walnut Hulls dates back to the Ancient Greeks and Romans, and they have been used by many cultures throughout history as an herbal tonic.&ampnbsp;&ampnbsp;The Black Walnut Tree is indigenous to the Middle East, but is currently grown in the U.S., Canada and Europe as well.