Also called "grandmother's flannel" for its thick, soft leaves, mullein is a common wildflower that can grow almost anywhere. It reaches several feet tall and puts up a spike of densely packed tiny yellow flowers. Mullein has served many purposes over the centuries, from making candlewicks to casting out evil spirits, but as medicine it was primarily used to treat diarrhea, respiratory diseases, and hemorrhoids.

Mullein contains a high proportion of mucilage (large sugar molecules); mucilage is generally thought to have a soothing effect. Mullein also contains saponins that may help loosen mucus.1  On this basis, mullein has been suggested as a treatment for asthma, colds, coughs, and sore throats. However, as yet there is no meaningful evidence that it is useful for any of these conditions.

Mullein is traditionally combined with other herbs in oil preparations to soothe the pain of ear infections (otitis media, or middle ear infection, but not “swimmer’s ear,” an external ear infection), and one study provides preliminary support for this use (see next section).

As with many herbs, test tube studieshave found that mullein can kill viruses on contact.3 In addition, an interesting but highly preliminary study suggests that mullein might help certain medications used for influenzawork better.4 These findings, however, are far too scant to show that internal use of mullein will fight viral infections.

Oral mullein is said to be most effective when combined with other herbs of similar qualities, such as yerba santa, marshmallow, cherry bark, and elecampane, but there is no evidence to support this belief.