- The only official benchmark for mullein tea is the European Medicines Agency’s 2018 monograph: 1.5 to 2 g of dried flower in 150 ml of boiling water, three to four times a day, for sore throat with a dry cough and cold.
- That approval rests on long traditional use, not clinical trials. No human study shows mullein tea detoxes the lungs, treats asthma or fights COVID-19.
- Most mullein tea sold in North America is made from the leaf, which the EU monograph does not cover; the flower is the regulated herbal substance.
- Strain every cup through a paper filter or tightly woven cloth. Mullein’s branched hairs can irritate skin, and loose fibres have no place in a cup meant to soothe a sore throat.
- Skip it in pregnancy, while breastfeeding and for children under 12, and see a doctor if a cough lasts more than a week.
What Mullein Tea Is (and Which Part of the Plant You Are Drinking)
Mullein tea is an infusion of Verbascum, a tall, felt-leaved plant in the figwort family. Three species count as medicinal mullein in Europe: great or common mullein (Verbascum thapsus), dense-flowered mullein (V. densiflorum, also listed as V. thapsiforme) and orange mullein (V. phlomoides). Those three are the species named in the European Union herbal monograph on mullein flower.
The part of the plant matters more than most guides admit. In the EU the regulated herbal substance is Verbasci flos, the dried flower. The ESCOP monograph narrows it further to the corolla and stamens, the yellow petals and their pollen-bearing parts. In the United States, mullein tea is usually sold and described as a leaf tea; Medical News Today’s July 2025 review, for example, defines it as tea made from the leaves. Leaf and flower share some constituents, but the dose, the indication and the safety record you read about in European sources were built on the flower.
Common mullein is a biennial. According to the USDA Forest Service’s Fire Effects Information System, it spends its first year as a ground-hugging rosette of furry leaves 8 to 50 cm long, then sends up a single stout flowering stalk that can pass 2 metres in its second summer.
Like every herbal infusion, mullein contains no tea leaf and no caffeine; our guide to how much caffeine is in tea shows where it sits alongside true teas.
Where You Will Meet Mullein on the Road
Mullein is native to Europe and Asia, and in North America it is an introduced plant that hikers pass on dry trails across the continent. The Colorado Weed Management Association notes it was first recorded on the continent in the mid-1700s, and the Forest Service traces its arrival to settlers who planted the seed before the Revolutionary War partly, in the Forest Service’s words, for the easy collection of fish. It now grows in every US state, Alaska and Hawaii included.
In the Rockies you will see the woolly rosettes and candle-like spikes along roadsides and in burned or disturbed ground. The Independence Pass Foundation photographed one at Weller Curve, around 9,500 feet on the road over the pass above Aspen. Colorado lists common mullein on its Noxious Weed List C, and the association records flowering from June through August, with spikes that can exceed 20 inches and stems up to six feet.
The plant’s staying power explains why it is everywhere. Michigan plants averaged about 175,000 seeds each in Forest Service data, and seed recovered from Danish soil dated to around 1300 AD still germinated. The thick coat of branched hairs that gives the leaves their flannel feel slows water loss in dry, windy sites. Folk names follow suit: flannel plant, velvet dock, Jupiter’s staff.
If you are tempted to pick some on a hike, two cautions apply. Plants along roads and in industrial lots, both favoured habitats, sit in runoff and exhaust. And the plant you see in July in Colorado is a declared weed in a landscape that land managers are trying to control, so check local rules on collecting plants in parks and protected areas before you pick anything.
Mullein Tea Benefits: What the Evidence Actually Supports
The strongest statement any regulator has made about mullein is narrow. In 2018 the EMA’s Committee on Herbal Medicinal Products adopted a revised monograph classing mullein flower as a traditional herbal medicinal product used to relieve symptoms of sore throat associated with dry cough and cold. Traditional means the committee accepted at least 30 years of use, including 15 in the EU, and found the effect plausible; it also noted the lack of clinical studies on mullein flower medicines. The EMA product page shows the monograph is under periodic review: a call for new scientific data ran from April to June 2024, and an addendum to the assessment report was published on 13 March 2025.
The European Scientific Cooperative on Phytotherapy (ESCOP), in its 2014 monograph, gives a similar indication: common cold with cough and sore throat, as a demulcent and mild expectorant. Demulcent describes the soothing, coating feel of the plant’s mucilage and polysaccharides on an irritated throat. That modest effect is the honest centre of mullein’s reputation.
The lab results and the teacup gap
Beyond the throat, mullein’s reputation is built mostly in test tubes. Reviews cite antiviral, antibacterial, antioxidant and anti-inflammatory activity from extracts and isolated compounds, plus anti-inflammatory and pain-reducing effects in animals. None of that tells you what a strained cup does in a person. Medical News Today points to a 2025 study of aqueous infusions in Applied Sciences that found no effect against E. coli or Staphylococcus aureus, a useful reminder that what a concentrated extract does on a lab plate and what hot-water tea does are different questions.
Lung detox, asthma and COVID-19 claims
Mullein went viral as a lung cleanse. Pulmonologist Dr. Madhav Chopra of Banner University Medicine told Banner Health in September 2025 that the lungs clean themselves by producing mucus that traps dust and bacteria, and that shortness of breath, a worsening cough, fever, night sweats or unexplained weight loss call for medical care rather than a detox. A 2023 review by Science Feedback rated the social-media claim that mullein treats COVID-19 as unsupported; a PubMed search turned up no studies and ClinicalTrials.gov listed no mullein trials with results.
| Claim | Best available evidence | Verdict for a cup of tea |
|---|---|---|
| Soothes a sore throat with a dry cough during a cold | EMA traditional-use monograph (2018); ESCOP monograph (2014) | Plausible, modest; based on long use, not trials |
| Loosens mucus (mild expectorant) | ESCOP indication; traditional use | Plausible, unproven in people |
| Antibacterial or antiviral | Lab studies on extracts; a 2025 infusion study found no effect on E. coli or S. aureus | Not shown for tea |
| Lung detox for smokers | No human evidence; healthy lungs clear themselves | Unsupported |
| Treats asthma or COPD | No clinical trials; Banner Health warns it can irritate some people’s lungs | Unsupported; talk to your doctor |
| Treats COVID-19 | No studies found (Science Feedback, 2023) | Unsupported |
How to Brew Mullein Tea to the EU Dose
The EU monograph gives the only published dose with regulatory standing, and it is for the flower: 1.5 to 2 g of dried, cut mullein flower in 150 ml of boiling water, taken three to four times a day, for a daily total of 4.5 to 8 g. The monograph covers adults, the elderly and adolescents; it does not recommend use under 12 because there is not enough data.
- Weigh, do not scoop. Dried mullein flowers are light and fluffy, so a teaspoon measure is unreliable. A kitchen scale that reads to 0.1 g takes the guesswork out of 1.5 to 2 g.
- Use freshly boiled water. Pour 150 ml, roughly a small teacup, over the flowers.
- Steep covered. The monograph specifies an infusion but no steep time, so cover the cup to keep the heat in and let the flowers soak through fully before straining.
- Strain twice if needed. Pour through a paper coffee filter or a tightly woven cotton cloth. A standard mesh basket can let the fine hairs through, and loose fibres are the last thing an irritated throat needs.
- Drink warm, plain or with honey. The mild, faintly sweet flavour takes honey well, and honey is itself a familiar sore-throat remedy.
If you are using leaf tea bags, follow the packet; the EU dose was not set for leaf. Medical News Today describes home brewers steeping a handful of dried leaves in about 8 oz of boiling water for 30 minutes or more, which shows how loosely leaf tea is usually dosed. For general technique, see our guide to water, temperature and timing.
| Mullein flower | Mullein leaf | |
|---|---|---|
| EU regulatory status | EMA traditional-use monograph (2018), under periodic review since 2024 | Not covered by the EU monograph |
| Official dose | 1.5 to 2 g in 150 ml boiling water, 3 to 4 times daily | None; follow the product label |
| Typical retail form | Dried yellow petals | Cut leaf and tea bags, common in North America |
| Straining | Filter as a precaution | Leaves are densely coated in branched hairs; filter every cup |
| Age guidance | Over 12 (EMA) | No official guidance; apply the same caution |
Mullein Tea Side Effects and Who Should Skip It
Mullein has a clean safety record as a tea, with caveats. The EMA monograph lists undesirable effects as none known, and its only contraindication is hypersensitivity to the plant. Dr. Chopra told Banner Health there are no known significant side effects, while the article lists possible mild ones: upset stomach, skin irritation and allergic reactions.
The hairs
The branched hairs that coat the leaves are the most practical risk. The Colorado Weed Management Association notes they may irritate skin, and Medical News Today cites a 2019 case report of contact dermatitis in a child exposed to mullein and daisy-family plants, though the researchers could not pin it on mullein alone. Wear gloves to harvest and filter every cup.
Pregnancy, breastfeeding and children
The EMA states that safety in pregnancy and lactation has not been established and does not recommend use in either. It also does not recommend use under 12. Banner Health adds the same caution for pregnancy and breastfeeding.
Asthma, COPD and medicines
Banner Health advises people with asthma or COPD to check with a provider first, because mullein may help some people but can irritate others’ lungs, and notes possible interactions with some medications, especially diuretics or anti-inflammatories. Dr. Chopra also points out that US mullein products are not manufactured to a standard the way European herbal medicines are, so strength varies from brand to brand.
When to stop
The EMA sets a firm limit: if symptoms last longer than one week, or get worse while you are drinking it, see a doctor or qualified health practitioner. A cough that lingers past a week, or comes with fever or breathlessness, is a reason for a check-up, not a stronger brew.
Buying and Storing Mullein
When you buy, read the label for the part used. A packet that says Verbasci flos or mullein flower matches the European monograph; one that says mullein leaf is a different product, even if the marketing is the same. Look for a botanical name, a country of origin and a best-before date. Bright yellow, intact petals suggest careful drying; brown, crumbled flowers have lost quality.
Store dried mullein in an airtight, opaque tin away from heat and steam; flowers pick up moisture readily and can turn musty.
| When | What the plant is doing (North America) | What it means for tea |
|---|---|---|
| Year 1, spring to autumn | Flat rosette of woolly leaves | Leaf harvest season; no flowers yet |
| Year 2, June to August | Flowering spike, blooms opening a few at a time | Flower harvest; pick open blooms every few days |
| Late summer to autumn | Seed capsules ripen; plant dies after seeding | No usable flowers left |
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Frequently Asked Questions
What is mullein tea good for?
Mullein tea is best supported for soothing a sore throat with a dry cough during a cold. The European Medicines Agency recognises mullein flower for that use on the basis of long traditional use, not clinical trials. Claims that it detoxes the lungs, treats asthma or fights infections come from lab studies or social media, not human evidence.
How much mullein tea can I drink a day?
The EU monograph sets 1.5 to 2 g of dried mullein flower in 150 ml of boiling water, three to four times a day, which is 4.5 to 8 g in total. That dose applies to adults and adolescents over 12. If symptoms last longer than a week or get worse, stop and see a doctor.
Why do you strain mullein tea through a coffee filter?
Mullein is coated in fine branched hairs that can slip through a mesh strainer and are known to irritate skin. Pouring the infusion through a paper coffee filter or tightly woven cloth keeps them out of a cup meant to soothe the throat. This matters most with leaf tea, since the leaves carry a dense hair coat.
Is mullein tea safe during pregnancy?
No, it is not recommended. The European Medicines Agency states that safety during pregnancy and breastfeeding has not been established and does not recommend mullein in either period. Banner Health gives the same advice. If you have a cough or sore throat while pregnant, ask your midwife, doctor or pharmacist which remedies are suitable.
Is mullein leaf tea the same as mullein flower tea?
No. The EU monograph and its dose cover the dried flower of three Verbascum species, while most mullein tea sold in North America is cut leaf. Leaf tea has no official dose, carries a dense coat of hairs and has not been assessed by European regulators. Check the label for the plant part before comparing it with European guidance.