Indigo Herbs Indigo Herbs Mullein Leaf Tincture 100mlMullein Leaf Tincture is the active constituents of Verbascum extracted into ethanol. This traditional method maintains and preserves the naturally occurring constituents found in the plant. Mullein Leaf Tincture from Indigo Herbs is derived from high quality Mullein Leaf which has a long history of traditional use as an expectorant. This herbal tincture can be added to water or fruit juice and taken when required.