Slippery Elm (Ulmus rubra), a native North American tree, slippery or red elm bark was used both internally and externally by native Americans and early pioneer settlers. The inner bark is used for its soothing and emollient effects. Nature's Way slippery elm bark is harvested from wild trees by a conscientious stripping process that does not hinder the growth of the tree. Our product contains tree bark, produced by nature, ground to a usable form.