Bio-Botanica, Inc. Mullein Leaf In Propylene Glycol is a product from the plant family Scrophulariaceae, known by its Latin name Verbascum thapsus. This product consists of key chemical constituents such as flavonoids, triterpenoid saponins, volatile oil, and tannins, and it is categorized as a food/beverage/dietary supplement for respiratory and immune support. Mullein Leaf, also known as Verbascum thapsus L, is the common name for this herb. It is a flowering plant in the figwort family and is native to Europe, Asia, and the Mediterranean. It can be commonly found in fields and waste areas throughout the United States. The name "velvet plant" derives from the soft, velvety texture of its leaves. Herbalists in the United States and around the world recommend mullein for its natural respiratory health benefits and support for healthy mucous membranes.