Mullein

Verbascum thapsus L., common or great mullein, belongs to the figwort family, Scrophulariaceae, in the USDA PLANTS classification; NCBI Taxonomy files it as taxon 39388. The US Forest Service’s Fire Effects Information System (FEIS) describes it as a densely woolly, sturdy biennial. In the first year it forms a basal rosette of large furry leaves, up to 60 cm across according to Turker and Gurel (Phytotherapy Research 2005), above a thick taproot. In the second year it usually sends up one stout stem, more than 1 cm thick, that may exceed 2 metres, with smaller leaves running up into a dense spike of five-petalled yellow flowers. Each flower is open for a single day. Branched hairs cover the leaves, stems, calyces, and even the outsides of the petals, giving the plant its grey, flannel-like look; common names such as velvet plant and old man’s flannel describe the same feature.

Turker and Gurel describe the species as native to Europe and Asia, and a 2022 review by Gupta and colleagues adds northern Africa. It has spread far beyond that range. FEIS records it in every US state, including Alaska and Hawaii, and in all southern Canadian provinces, and USDA PLANTS lists it as introduced throughout North America. FEIS cites field studies in which plants averaged 100,000–175,000 tiny seeds each, and one well-developed plant produced 223,200; it also notes that seeds have germinated after 100 years or more in the soil. Mullein is mostly a short-lived plant of disturbed ground such as roadsides, burns, and old fields. Dense, persistent stands are a problem in parts of Hawaii and California; in Hawaii it was first recorded in 1932 and covered more than 2,000 km² by 1990.

Medicinal mullein flower in Europe is not one species. The European Pharmacopoeia definition, quoted by EMA, covers the dried corollas and stamens of V. thapsus, V. densiflorum (also called V. thapsiforme), and V. phlomoides, and EMA notes that the European tradition favoured the last two, which are uncommon in the UK and absent from the US. The flowers contain mucilage: EMA cites 2–3% water-soluble acidic polysaccharides, mainly an arabinogalactan, and the Pharmacopoeia sets a minimum swelling index of 9. They also contain iridoid glycosides including aucubin (PubChem CID 91458, C15H22O9) and catalpol; the phenylethanoid glycoside verbascoside, also called acteoside (CID 5281800, C29H36O15), at about 0.6% in V. densiflorum flowers; flavonoids such as luteolin and apigenin glycosides; and triterpene saponins, though EMA notes their content has never been reliably measured. Some reviews list hesperidin as a key constituent, but EMA reports that its presence was not confirmed on re-examination.

Mullein was a plant of light before it was a medicine. Turker and Gurel note that Greeks and Romans dipped the dried flowering stems in tallow to use as tapers, and FEIS cites the same Roman use as torches, along with the use of the yellow flowers to dye hair as early as the fourth century BC. EMA’s report adds suet or wax, the origin of names like hag taper and candlewick plant. The genus name Verbascum is thought to be a corruption of barbascum, from the Latin for beard, after the plant’s shaggy look, while mullein comes through Old French from the Latin mollis, soft, after the leaves (Turker and Gurel). In medicine, EMA notes that mullein preparations were used in the Middle Ages and that the German herbalist Lonicerus praised the plant in 1564 as an expectorant, a heart and fever medicine, and a remedy for warts.

European settlers carried mullein to North America, and not only as medicine. FEIS reports that before the Revolutionary War, settlers brought and cultivated the seeds to catch fish: crushed seeds were put into dammed-off pools of slow water, where they stopped the fish breathing, and fish “stings” became community events. Turker and Gurel date its introduction to Virginia as a fish poison to the mid-1700s and, citing a 1974 geographical study of mullein as a fish poison in mountain folk culture, list saponins, rotenone, and glycosides as the toxic elements, though that attribution rests on older literature rather than modern analysis of the seed. Native American nations also took up the plant. FEIS records that the Potawatomi, Mohegan, Penobscot, and Menominee smoked dried leaves for colds, bronchitis, and asthma, the Catawba made a cough syrup from the roots, and leaf poultices were used for bruises, sprains, and headaches.

Mullein then moved into official pharmacy. EMA notes that the 1918 Dispensatory of the United States described mullein flowers as official, that the British Herbal Pharmacopoeia of 1983 covered leaves and stems and its 1996 edition the leaf only, and that Germany’s Commission E approved mullein flower in 1990 for catarrhs of the respiratory tract at 3–4 g a day. Mullein flowers also became an ingredient of European chest teas: a Czech and Slovak blend on the market since 1969 combines them with plantain, marshmallow root, coltsfoot, peppermint, licorice, and fennel. The EU’s herbal committee adopted its first monograph on mullein flower on 3 July 2008 and a revised version on 27 March 2018, both granting traditional use only. Ear oils containing mullein were tested clinically in Israel in 2001 and 2003.

The best-supported explanation is physical. Mucilage, the swelling polysaccharide fraction that the European Pharmacopoeia measures through the swelling index, forms a slippery film that can coat and soothe an irritated throat, the property herbalists call demulcent. When EMA first assessed mullein in 2008, it concluded that the traditional use in cough and colds is in particular as a demulcent, which is why the EU indication is worded around relieving sore throat with a dry cough rather than treating infection or clearing the chest. Saponins have traditionally been credited with an expectorant effect, loosening mucus, but the one experiment EMA cites found that a water extract of mullein flower had no effect on mucus transport in isolated frog oesophagus, a test EMA notes has limitations. There are no pharmacokinetic data for mullein in humans.

Laboratory studies describe broader activity that has not been tested in people. EMA summarises cell-culture work in which mullein flower infusions reduced the growth of several influenza strains and inactivated herpes simplex virus type 1, and a 2002 study in which mullein flowers extracted in olive oil inhibited Klebsiella pneumoniae, Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus. Purified constituents show anti-inflammatory and analgesic effects in rodents: aucubin at 100 mg/kg by mouth reduced paw swelling in rats, and verbascoside reduced inflammation and pain responses in several animal models. Gupta and colleagues (Phytotherapy Research 2022) review many more such studies. EMA concludes that experimental results supporting the traditional indication are limited, and the doses of isolated compounds used in animals bear no clear relation to a cup of tea.

The hairs matter as much as the chemistry. Turker and Gurel describe the dense, star-shaped branched hairs as a defence that reduces water loss, deters creeping insects, and sets up intense irritation in the mucous membranes of grazing animals. They quote the herbalist Maud Grieve that mullein tea must always be strained through fine muslin, because hairs left floating in the infusion can cause intolerable itching in the mouth. On safety pharmacology, EMA notes one laboratory study in which verbascoside caused chromosome damage in stimulated human lymphocytes; mullein flower itself has never had genotoxicity testing, which is why EMA declined to add it to the EU list of traditional herbal substances.

Sore throat with a dry cough: this is the only use the EU herbal committee accepts. Its 2018 monograph classes mullein flower as a traditional herbal medicinal product used to relieve symptoms of sore throat associated with dry cough and cold, based on more than 30 years of medicinal use, including at least 15 in the EU. The assessment report is unusually blunt: under clinical efficacy, dose–response studies, and clinical trials it records “No data found”, and it concludes that there are no data on clinical pharmacology or efficacy for mullein flower. Mullein tea may well soothe a raw throat in the same way as other warm, mucilaginous drinks, but there is no trial showing that it shortens a cold, reduces coughing, or treats bronchitis.

Ear pain from acute otitis media: Sarrell, Mandelberg, and Cohen (Archives of Pediatrics and Adolescent Medicine 2001) randomised 103 children aged 6 to 18 with ear pain from acute otitis media to Otikon, an olive-oil drop containing garlic, mullein, calendula, and St John’s wort, or to anaesthetic drops containing ametocaine and phenazone. Pain improved significantly over three days in both groups, and the two treatments were comparable. Sarrell, Cohen, and Kahan (Pediatrics 2003) then randomised 171 children aged 5 to 18 to herbal drops, which also contained lavender and vitamin E, or anaesthetic drops, with or without oral amoxicillin. Every group improved; children given drops alone did better than those also given amoxicillin, and results were somewhat better with the herbal drops.

The limits of the ear evidence are substantial. In the 2003 trial, the authors concluded that about 80% of the pain was self-limited and could be explained simply by the passage of time, and that the most effective treatment explained only 7.3% of the total pain reduction. Neither trial had a placebo arm, both tested multi-ingredient products in which mullein’s contribution cannot be separated from garlic, calendula, or St John’s wort, and both were run by the same lead author. Foxlee and colleagues (Cochrane 2006) found three trials sharing a co-author that compared naturopathic and anaesthetic drops in 274 patients, always favouring the herbal drops, but concluded that the evidence was insufficient to know whether ear drops are effective or not. The review considered only otitis media without a perforated eardrum.

Lung detox claims: mullein is widely marketed to cleanse, detox, or repair the lungs, particularly for smokers and people who vape. No clinical trial supports this. EMA found no clinical studies of mullein for any indication, and the evidence base reviewed by Gupta and colleagues consists of laboratory and animal work. There is no evidence that mullein removes tar, particles, or toxins from the lungs, reverses smoking damage, or treats asthma or chronic obstructive pulmonary disease. Historical accounts of smoking mullein leaves for asthma, recorded by FEIS and Turker and Gurel, describe tradition, not tested benefit, and smoke of any kind irritates the airways. People with a chronic cough, wheeze, or breathlessness need assessment and proven treatment.

Other uses: Taleb and Saeedi (BMC Complementary Medicine and Therapies 2021) randomised 93 first-time mothers in Iran to a mullein cream or placebo cream applied to episiotomy wounds twice daily for 10 days. Healing scores did not differ on days 1 and 3 but were significantly better with mullein on day 10, a single small trial that needs replication. FEIS summarises folk uses for tuberculosis, pneumonia, urinary infections, skin diseases, haemorrhoids, diarrhoea, warts, migraine, frostbite, and ringworm, and EMA records traditional external use of flower decoctions on wounds, burns, and bedsores. None of these has clinical support, and serious infections such as tuberculosis and pneumonia need medical treatment.

EU traditional use (EMA/HMPC/611537/2016, adopted 27 March 2018), for adolescents over 12, adults, and the elderly: 1.5–2 g of dried, cut mullein flower infused in 150 ml of boiling water, three to four times daily, a daily dose of 4.5–8 g. Not recommended under 12 because of a lack of adequate data. If symptoms persist for more than a week, or worsen, see a doctor or qualified practitioner, and see one promptly if breathlessness, fever, or purulent sputum develops. Products on the Polish market summarised by EMA use 1 g of flower in 150 ml, infused covered for 10–15 minutes and strained, and syrups made from fluid extracts, labelled for no longer than a week. Germany’s 1990 Commission E monograph gave 3–4 g of flower a day.

Strain every mullein infusion through fine cloth, muslin, or a paper coffee filter rather than a tea strainer, because loose hairs from the flowers and especially the felted leaves can irritate the mouth and throat (Turker and Gurel, quoting Grieve). The EU monograph covers the flower only; leaf teas are widely sold, particularly in North America, but have no regulatory dose. Tinctures and fluid extracts contain alcohol. Mullein capsules and “lung cleanse” blends often combine mullein with other herbs, so check every ingredient; licorice, for example, has its own cautions and interactions. Buy products labelled with the Latin name Verbascum, because the common name gordolobo is applied to other plants.

Mullein ear oils, often combined with garlic, are sold for earache. In the 2003 Israeli trial, children received five drops three times daily, with pain assessed over three days. Use ear drops only after a clinician has examined the ear: never put oil or drops into an ear that is discharging, may have a perforated eardrum, or has grommets (ear tubes), and seek care for ear pain with fever, swelling behind the ear, or hearing loss. Mullein seeds are not a remedy; FEIS notes they were used to poison fish. Smoking mullein leaf, sometimes sold as a tobacco substitute, is not recommended for any health purpose.