Therapeutic uses cough
* Internal use
o The saponins contained in the herb help to loosen and remove mucus from the lungs, while the mucilage soothes the mucus membranes and the iridoid glycosides help to fight inflammation.
o Internally, it is used for coughs, whooping cough, bronchitis, laryngitis, tonsillitis, tracheitis, asthma, influenza, tuberculosis, urinary tract infections, nervous tension, and insomnia.
o Although it is particularly effective to loosen mucus in the lungs it also shows some success with reducing water retention.
o Historically it was also used for genito-urinary tract infections.
* External use
o Externally, mullein is used to treat earache, specifically chronic otitis media (the flowers are macerated in olive oil), sores, eczema (especially around the ear), wounds, boils, rheumatic pain, hemorrhoids and chilblains.
o The saponins contained in the herb help to loosen and remove mucus from the lungs, while the mucilage soothes the mucus membranes and the iridoid glycosides help to fight inflammation.
o Internally, it is used for coughs, whooping cough, bronchitis, laryngitis, tonsillitis, tracheitis, asthma, influenza, tuberculosis, urinary tract infections, nervous tension, and insomnia.
o Although it is particularly effective to loosen mucus in the lungs it also shows some success with reducing water retention.
o Historically it was also used for genito-urinary tract infections.
* External use
o Externally, mullein is used to treat earache, specifically chronic otitis media (the flowers are macerated in olive oil), sores, eczema (especially around the ear), wounds, boils, rheumatic pain, hemorrhoids and chilblains.
Common Mullein as Food and Habitat for Wildlife
Fairfax County Public Schools has a beautiful page on mullein with photos and a discussion of how wildlife uses mullein. Their site explains:
Only a few animals use mullein for food. Certain species of thrips, stinkbugs, weevils, and leaf bugs will eat mullein leaves; but these are insects which were brought over from Europe. Short-horned Grasshoppers, such as the Differential Grasshopper, will also eat leaves.American Goldfinches, Indigo Buntings, and a few other birds eat mullein seeds.Common Mullein provide shelter for insects in the winter. Since rosettes survive through the cold weather, leaves provide warm and protection for ladybugs, plant bugs, and black bugs, among others.Hummingbirds sometimes use the soft leaves to line their nests.Many insects come to mullein flowers for nectar. Bumble bees, honey bees, and hover flies help pollinate these plants.Several species of fungi become parasites of Common Mullein, including Powdery Mildew.
Medicinal Uses of Common Mullein
The Alternative Nature Herbal discusses the medicinal properties of mullein. (Please visit their site to view the full article.)
Great Mullein has been used as an alternative medicine for centuries, and in many countries throughout the world, the value of Great Mullein as a proven medicinal herb is now backed by scientific evidence. Some valuable constituents contained in Mullein are Coumarin and Hesperidin, they exhibit many healing abilities. Research indicates some of the uses as analgesic, antihistaminic, anti-inflammatory, anticancer, antioxidant, antiviral, bacteristat, cardio-depressant, estrogenic, fungicide, hypnotic, sedative and pesticide are valid.An infusion is taken internally in the treatment of a wide range of chest complaints and also to treat diarrhea and bleeding of the lungs and bowels. The leaves, root, and the flowers are anodyne, anti-inflammatory, antiseptic, antispasmodic, astringent, demulcent, diuretic, emollient, expectorant, nervine, and vulnerary.Mullein oil is a very medicinal and valuable destroyer of disease germs. An infusion of the flowers in olive oil is used as earache drops, or as a local application in the treatment of piles and other mucous membrane inflammations. This infusion is a strong antibacterial. The oil being used to treat gum and mouth ulcers is very effective. A decoction of the roots is used to alleviate toothache and also relieve cramps and convulsions. It is also used in alternative medicine for the treatment of migraine headaches accompanied with oppression of the ear.The whole plant possess slightly sedative and narcotic properties. The seeds are considered toxic. They have been historically used as a narcotic and also contain saponins.The dried leaves are sometimes smoked to relieve the irritation of the respiratory mucus membranes, and the hacking cough of consumption. They can be employed with equal benefit when made into cigarettes, for asthma and spasmodic coughs in general. Externally, a medicinal poultice of the leaves is applied to sunburn, ulcers, tumors and piles.
I have used a tea made from the dried leaves to calm a cough. We haven’t had any ear problems since I started harvesting mullein, so I can’t vouch for other uses. You can view how to dry the flowers and leaves in the post Wildcrafting 101. Mullein also contains coumarin and rotenone – a naturally occurring pesticide. For more ideas on how to use mullein medicinally, visit kingdomPlantea.net.
Other Uses of Common Mullein
The dried flower stalks were dipped in tallow and used as torches by Roman soldiers (and probably others as well). The leaves were placed in footwear as extra padding and to help keep feet warm. The leaves produce a mild irritation/redness when rub against the skin, which led to the plant being used in the Victorian age as rouge. Supposedly it’s one of the best leaves to use to wipe your backside when you’re out squatting in the woods, but I haven’t yet tried this. 
Mullein can also be using for dying. KingdomPlantae states that, “The flowers make a bright yellow dye, which can be used to dye hair or cloth. The addition of sulfuric acid will produce a color-fast green. If you then add an alkali, to raise the Ph, the dye becomes brown.”