Mullein is most often used to treat coughs, colds, and respiratory diseases. It is mucilaginous and soothing to the mucus membranes, and is used to break up congestion and stop spasms of coughing, and to relax the bronchia, making it often useful in asthma attacks.
Mullein creates a mucilaginous layer of protection on the inflamed membranes to which it is applied, both soothing them and protecting from further injury. When this action is used in the respiratory system, Mullein may stop the absorption of allergens into the mucus membranes, preventing allergy attacks and related discomfort.
Mullein also has been said to have pain-killing and mild narcotic properties, calming the nerves and helping the patient relax and rest to recuperate.