* Herbal Throat Support * Herbal Supplement Slippery Elm (Ulmas Rubra) is a tree native to North America. The inner bark has been used for generations to soothe minor throat irritation associated with exposure to dust, excessive talking and other everyday activities. These Planetary Herbals great-tasting tangerine-flavored Slippery Elm Lozenges contain echinacea and vitamin C for immune support.