Mullein tea is best known as a remedy for dry coughs, sore throats, and colds. It has a long history in European herbal medicine, and the European Medicines Agency officially recognizes mullein flower as a traditional herbal product for relieving sore throat symptoms associated with dry cough and cold. Beyond respiratory support, the plant contains compounds with anti-inflammatory and antimicrobial properties that give it a broader range of traditional uses.
Soothing Dry Coughs and Sore Throats
Mullein’s most established use is for upper respiratory discomfort, particularly the scratchy, irritated feeling of a dry cough or sore throat. The flowers and leaves contain about 3% mucilage, a gel-like substance made of complex sugars. When you drink mullein tea, this mucilage coats the lining of your throat and airways, forming a protective layer that reduces irritation and calms the urge to cough. This is what herbalists call a “demulcent” effect, and it’s the same basic principle behind honey coating a sore throat.
Mullein also contains saponins, compounds that foam when dissolved in water. Saponins have expectorant and anti-cough effects, which means they can help loosen mucus in the airways so it’s easier to clear. The combination of mucilage soothing irritation and saponins helping move mucus is what makes mullein tea a go-to for colds. It works on both ends of the problem: calming the cough reflex while helping your body clear congestion.
That said, formal clinical trials on mullein tea specifically are limited. The EMA’s recognition is based on decades of consistent traditional use rather than large-scale human studies. This doesn’t mean it’s ineffective, just that the evidence is experiential rather than clinical.
Anti-Inflammatory Compounds
One of mullein’s most studied compounds is verbascoside, a plant chemical with notable anti-inflammatory activity. In animal studies, verbascoside reduced key inflammatory signals including TNF-alpha, IL-1 beta, and IL-6. These are proteins your immune system produces during inflammation, and they drive the swelling, pain, and redness you feel during infections or injuries. In one study modeling acute lung injury, verbascoside lowered levels of all three of these inflammatory markers in lung fluid.
Mullein is also rich in flavonoids, including apigenin, luteolin, kaempferol, and rutin. Flavonoids are a broad class of plant compounds known for antioxidant and anti-inflammatory effects. Together with phenolic acids like caffeic acid and ferulic acid, these compounds give mullein tea a mild but multi-layered anti-inflammatory profile. This likely contributes to why the tea feels soothing beyond just coating the throat: it may be reducing some of the inflammation driving the discomfort in the first place.
Antimicrobial Activity
Lab studies show mullein extracts have antibacterial activity against a surprisingly wide range of organisms. Leaf extracts have inhibited the growth of Staphylococcus aureus, E. coli, Klebsiella pneumoniae, and several species of Bacillus bacteria. One study found that mullein extract also disrupted biofilm formation by oral streptococci, the bacteria responsible for dental plaque, at concentrations as low as 0.50 mg/ml.
There’s also early evidence of antiviral activity. Mullein extracts showed activity against herpes simplex virus type 1 in laboratory testing. These antimicrobial properties are attributed to the plant’s glycosides, alkaloids, and flavonoids working together. It’s worth noting that lab-dish results don’t automatically translate to what happens when you drink a cup of tea, but they do help explain why mullein has been used for centuries during infections.
Digestive and Other Traditional Uses
The same mucilage that soothes your throat can also coat and calm an irritated digestive tract. Mullein has been traditionally used for intestinal discomfort, and saponins in the plant have mild laxative effects. Some herbalists also recommend it for mild urinary complaints, as saponins have diuretic properties. These uses are less well-documented than respiratory applications, but they stem from the same active compounds.
How to Prepare Mullein Tea
The standard preparation is one to two teaspoons of dried mullein leaves or flowers per cup of boiling water. Let it steep for 10 to 15 minutes, then strain thoroughly. Traditional daily use was in the range of 3 to 4 grams of dried herb total, which works out to roughly three or four cups a day.
Straining is the most important step, and a regular tea strainer isn’t fine enough. Mullein leaves are covered in tiny hairs called trichomes. If these get into your tea, they can irritate your throat and respiratory tract, which is the opposite of what you’re going for. Use a coffee filter, fine cheesecloth, or a paper tea filter to catch every last hair. This one extra step makes the difference between a soothing cup and one that leaves you coughing.
Safety and Side Effects
Mullein tea is generally well tolerated and has no widely reported serious side effects at normal doses. The main risk is the throat irritation from unfiltered plant hairs mentioned above. Saponins in mullein can destroy red blood cell membranes in a lab setting, but the concentrations in a cup of tea are far below levels that would cause problems in your body.
Because there’s limited clinical research, there’s also limited data on interactions with medications or safety during pregnancy. If you’re taking prescription drugs or are pregnant, it’s reasonable to check with a healthcare provider before making mullein tea a daily habit. For most people drinking a few cups during a cold, the risk profile is very low.