Mullein is a tall, fuzzy plant from Europe and Asia that now grows wild across most of North America, typically along roadsides, in empty lots, and on dry, disturbed ground. Its scientific name is Verbascum thapsus, and it belongs to a genus of 465 recognized species. You’ve likely walked past it without knowing its name: a large rosette of velvety gray-green leaves hugging the ground, or a towering stalk topped with small yellow flowers. It has a long history as a folk remedy for coughs and lung complaints, and it’s recently surged in popularity as an herbal tea and supplement.
How to Identify Mullein
Mullein is a biennial, meaning it takes two years to complete its life cycle. In its first year, it stays low to the ground as a rosette of large, oval leaves that can be a foot long. These leaves are its most distinctive feature: they’re covered in a thick layer of soft, woolly hairs that make the whole plant feel like flannel. The color is a pale, dusty green, sometimes almost silver.
In the second year, a single sturdy stalk shoots up from the center of the rosette, reaching up to six feet tall. The stalk is densely packed with small, five-petaled yellow flowers that open a few at a time over the course of summer. After flowering and setting seed, the entire plant dies. A single mullein can produce over 100,000 tiny seeds, which can remain viable in the soil for decades, waiting for the right conditions to germinate.
Distinguishing Mullein From Foxglove
Before flowers appear, mullein’s leafy rosette can look similar to foxglove, which is highly toxic. The key difference is texture and leaf edges. Mullein leaves are noticeably hairier and have smooth, untoothed margins. Foxglove leaves have toothed edges, a darker green color, and less prominent fuzz. Once flowers appear, there’s no confusion: foxglove produces tall spikes of tubular purple or pink bells, while mullein has small, flat yellow flowers clustered along a thick central spike.
Where Mullein Grows
Mullein is native to Europe, northern Africa, and parts of Asia. It was introduced to North America in the early 1600s and has since spread to every U.S. state. It thrives in full sun and well-drained or gravelly soil, which is why you see it along highways, railroad tracks, burned hillsides, and construction sites.
In the eastern United States, the U.S. Forest Service considers mullein generally restricted to disturbed sites and not especially invasive in undisturbed habitats. In the West, however, it can be more aggressive. In California’s Mono Lake and Owens Valley, mullein populations have colonized intact, undisturbed meadows. In the western Sierra Nevada, it moves in almost immediately after wildfire and may crowd out native grasses and wildflowers during the early stages of recovery.
Hawaii is where mullein causes the most ecological concern. On Mauna Kea, researchers found that removing mullein from experimental plots increased the cover of native grasses, suggesting the plant was actively suppressing them. Feral sheep and goat grazing likely helped mullein establish itself in niches once occupied by the endangered Hawaiian silversword.
Traditional Uses Through History
Mullein has been used medicinally since at least the first century, when the Greek physician Dioscorides recommended the root taken in wine. In medieval Europe, monks cultivated it in their gardens. It became a go-to remedy for tuberculosis in Northern Europe, where it was considered the best available treatment for persistent coughs.
The plant had plenty of non-medical uses, too. Roman legionaries dipped the dried stalks in tallow and used them as torches. Roman women washed their hair with a preparation of the flowers to dye it golden. The fine fuzz covering the leaves and stems is extremely flammable and was used as candle wick material before cotton became widespread. In Greece and elsewhere, the seeds were tossed into water to stun fish, making them easier to catch.
After arriving in North America, mullein was quickly adopted by Indigenous peoples. The Cherokee, Creek, Delaware, and Iroquois all used it, typically brewed as tea or syrup, for coughs and croup. Many groups applied poultices of the leaves to wounds, bruises, and swellings. The Delaware heated leaf poultices and applied them to joints for rheumatism. The Cherokee wrapped leaves around the neck to treat swollen glands and mumps. The Iroquois smoked the dried leaves for asthma and respiratory congestion, and the Abenaki placed mullein root necklaces on teething babies.
What’s Inside the Plant
Mullein’s reputation as a respiratory herb traces back to two main groups of compounds. The leaves and flowers contain a high concentration of mucilage, a gel-like substance made of complex sugars. When you brew mullein into tea, this mucilage dissolves into the water and coats irritated mucous membranes in the throat and airways, which is why it feels soothing to drink when you have a cough. The plant also contains saponins, compounds that act as natural expectorants by helping loosen and thin mucus so it’s easier to cough up.
Beyond those two, mullein contains flavonoids (plant-based compounds with antioxidant properties) and volatile oils. The flowers are richer in mucilage, while the leaves tend to have higher concentrations of certain compounds involved in reducing inflammation.
What Modern Research Shows
Lab studies have found promising results for mullein. Stem extract combined with alcohol was 85% effective at protecting cells from damage in one study. Another found mullein effective against bacteria that cause pneumonia and staph infections, as well as E. coli. There’s also evidence it may slow the influenza virus in laboratory settings.
The catch is that these are mostly test-tube and animal studies, not large clinical trials in humans. In European countries like Germany, mullein-based products are manufactured under standardized conditions, which makes dosing more consistent and reliable. In the United States, mullein supplements and teas aren’t produced with the same standardization, so the potency and quality of what you buy can vary significantly from one brand to the next.
How to Prepare Mullein Tea
If you want to try mullein, tea is the most common preparation. For a hot infusion, place about one tablespoon of dried mullein leaves in a cup and pour boiling water over them. Let it steep for 10 to 15 minutes. The one essential step: strain the tea through a fine mesh sieve or cheesecloth. Those tiny hairs that make the plant so soft can irritate your throat if they end up in your cup.
A cold brew method also works well and produces a milder, slightly sweeter result. Add one to two teaspoons of dried leaves per cup of cold filtered water in a glass jar, and let it steep in the refrigerator for 8 to 12 hours or overnight. Strain it the same way before drinking. The flowers can be used alone or blended with the leaves, and some people find the flower tea gentler in flavor.