Lungwort (Pulmonaria officinalis) has centuries of traditional use as a respiratory remedy, but the honest state of the science is that no human clinical trials have confirmed any of its purported health benefits. What does exist is a growing body of lab research showing the plant is rich in phenolic compounds with real antioxidant and anti-inflammatory activity in test tubes and cell models. Whether those effects translate to meaningful results inside a living person remains an open question, and the plant carries safety risks that deserve attention before anyone brews a cup.
Why the Plant Is Called Lungwort
The name traces back to the Doctrine of Signatures, an old European idea that a plant’s appearance signals what it can treat. Lungwort leaves are spotted with pale blotches that, to medieval herbalists, looked like diseased lung tissue. That resemblance was enough for them to prescribe it for coughs, bronchitis, and other chest complaints. The Latin genus name Pulmonaria comes directly from pulmo, meaning lung. Traditional healers across central and eastern Europe used infusions of the dried leaves and flowering tops as expectorants and demulcents, hoping to soothe irritated airways and loosen phlegm.
It is worth flagging early that traditional use, even widespread and long-standing, is not the same as clinical evidence. Many plants used for centuries turned out to contain genuinely active compounds. Others turned out to do nothing, or worse, to cause harm. Lungwort sits in an awkward middle ground: the chemistry is interesting, the lab data are promising, and the human data are essentially absent.
What Is Actually in the Plant
The most detailed chemical profiling of Pulmonaria officinalis has revealed a complex cocktail of phenolic compounds. Researchers using advanced chromatography techniques identified caffeic acid esters bound to aliphatic hydroxycarboxylic acids, conjugates of dicaffeic acid with rosmarinic acid, and previously unknown isomers of compounds called isosalvianolic acid A and yunnaneic acid E, along with various lignans.1PubMed Central. Novel Phenolic Constituents of Pulmonaria officinalis L. LC-MS/MS Comparison of Spring and Autumn Metabolite Profiles Rosmarinic acid is a standout ingredient because it appears in several well-studied herbs (rosemary, sage, lemon balm) and has documented antioxidant and anti-inflammatory effects in lab settings.
The phenolic content is not trivial. When researchers compared the antioxidant capacity of seven Bulgarian medicinal plants, lungwort ranked among the highest for total phenolics and overall antioxidant strength.2Journal of Ethnopharmacology. Polyphenols and antioxidant capacity of Bulgarian medicinal plants That finding matters because phenolics are the class of compounds most likely to explain any real biological activity in the plant. The seasonal timing of harvest also affects what you get: the spring and autumn metabolite profiles differ, which means two batches of dried lungwort could contain meaningfully different chemical mixtures depending on when the plant was collected.
Antioxidant and Anti-Inflammatory Effects in the Lab
The most detailed work on lungwort’s biological activity has been done in vitro, meaning in isolated cells or blood plasma rather than in living people. One comparative study tested phenolic-rich fractions from P. officinalis and the closely related P. obscura against peroxynitrite-induced oxidative stress in human blood plasma. Peroxynitrite is a reactive molecule that damages proteins and lipids in the body, and the lungwort extracts partly prevented that damage while also improving the plasma’s overall non-enzymatic antioxidant capacity.3PubMed Central. Pulmonaria obscura and Pulmonaria officinalis Extracts as Mitigators of Peroxynitrite-Induced Oxidative Stress and Cyclooxygenase-2 Inhibitors – In Vitro and In Silico Studies
The same study looked at whether the extracts could inhibit cyclooxygenase-2, the enzyme commonly known as COX-2. This is the same enzyme that non-steroidal anti-inflammatory drugs like ibuprofen target. The P. officinalis extract showed stronger COX-2 inhibition than its close relative, with the researchers identifying ten individual compounds capable of binding to the enzyme, including rosmarinic acid and several others.3PubMed Central. Pulmonaria obscura and Pulmonaria officinalis Extracts as Mitigators of Peroxynitrite-Induced Oxidative Stress and Cyclooxygenase-2 Inhibitors – In Vitro and In Silico Studies Computer modeling (in silico analysis) further confirmed these binding interactions, giving some mechanistic plausibility to the idea that lungwort’s phenolics could have an anti-inflammatory effect.
All of that sounds encouraging, but a hard truth about in vitro research applies here: exposing isolated blood plasma or a purified enzyme to a plant extract in a dish is fundamentally different from swallowing that extract and expecting it to reach the right tissues in the right concentration. Digestive enzymes break down many phenolic compounds. The liver metabolizes others before they ever reach the bloodstream in their active form. Until someone runs controlled trials in people measuring actual inflammation markers or clinical outcomes, the antioxidant and anti-inflammatory data remain suggestive rather than proven.
Respiratory Benefits Are Still Folkloric
If you search for lungwort, you will find claims that it helps with asthma, chronic bronchitis, coughs, and general lung health. These claims trace almost entirely to traditional use, not to clinical evidence. No published randomized trial has tested lungwort for any respiratory condition against a placebo. The mucilage content of the plant (a thick, gel-like substance found in the leaves) does have soothing properties when it coats irritated mucous membranes, which is why herbalists classify lungwort as a demulcent. But many plants contain mucilage, and the soothing effect of a warm herbal infusion on a sore throat is not the same as treating a respiratory disease.
Some herbal medicine practitioners also point to lungwort’s allantoin content. Allantoin is a compound used in wound-healing creams and is thought to promote cell regeneration. Whether drinking an infusion delivers enough allantoin to the airways to matter is unknown. The gap between “this compound exists in the plant” and “drinking the plant delivers a clinically relevant dose of that compound to a target organ” is enormous, and lungwort’s respiratory claims have never crossed it with published data.
A Serious Poisoning Case Worth Knowing About
One of the most striking pieces of evidence in the lungwort literature is not about benefits at all. A case report described three members of the same family in Spain who developed atropine-like poisoning after drinking a lungwort infusion. The grandmother experienced intense mouth dryness, dilated pupils, dizziness, weakness in her legs, and urinary retention. During her episodes she became disoriented, had visual hallucinations, slurred speech, and memory impairments. Her 42-year-old daughter developed dry mouth, blurred vision, urinary retention, severe anxiety, and palpitations. The 14-year-old granddaughter, who had been given the infusion for a common cold, also developed blurred vision, dry mouth, and urinary retention; after continuing to drink the infusion over the next several hours, she became disoriented and experienced psychomotor agitation and visual hallucinations.4The European Journal of Psychiatry. Acute atropine intoxication with psychiatric symptoms by herbal infusion of Pulmonaria officinalis (Lungwort)
The symptoms are consistent with anticholinergic toxicity, which blocks the neurotransmitter acetylcholine and affects the nervous system, eyes, bladder, and brain. The exact source of the atropine-like compounds was not definitively identified, and one possibility raised by the authors is contamination or adulteration of the herbal product rather than an inherent property of pure Pulmonaria officinalis. Plants in the Boraginaceae family (the family lungwort belongs to) can sometimes be confused with or contaminated by other species that produce tropane alkaloids. Regardless of the mechanism, the case is a concrete reminder that “herbal” and “natural” do not mean “safe,” and that unregulated herbal products carry contamination risks that pharmaceutical drugs do not.
Pyrrolizidine Alkaloids and Liver Safety
Beyond the acute poisoning case, there is a slower and more insidious concern with lungwort and many other plants in its botanical family: pyrrolizidine alkaloids (PAs). These are naturally occurring toxins found in hundreds of plant species, and the Boraginaceae family is one of the major sources. PAs can cause a type of liver damage called hepatic veno-occlusive disease, and some are classified as potentially carcinogenic. The damage tends to be cumulative, meaning it builds up with repeated exposure rather than showing up after a single cup of tea.
A refined risk assessment of PAs in herbal teas and plant food supplements found that over half of the herbal tea types tested had PA levels high enough to raise regulatory concern, with the calculated margins of exposure falling below the threshold considered acceptable for compounds with possible genotoxic effects.5PubMed. Risk assessment for pyrrolizidine alkaloids detected in (herbal) teas and plant food supplements That study examined herbal teas broadly, not lungwort specifically, but the finding is directly relevant because lungwort is a Boraginaceae species and is consumed as a herbal tea. The European Medicines Agency and the German Federal Institute for Risk Assessment have both issued warnings about PA-containing plants and recommend limiting exposure.
If you are thinking about using lungwort regularly, the PA question is probably the most important practical concern. Occasional use in small amounts is likely low-risk for most people, but daily or long-term consumption of an unregulated herbal product without PA testing is a gamble with your liver health. Products labeled as “PA-free” or “detoxified” exist for some Boraginaceae herbs (comfrey is the best-known example), but such guarantees depend entirely on the manufacturer’s quality control, and the supplement market’s track record on that front is uneven.
Anti-Coagulant Activity and Drug Interactions
A review of plants with anti-coagulant activity included Pulmonaria officinalis among the species shown to thin the blood, alongside better-known examples. The review’s authors specifically warned that medicinal plants with anti-coagulant properties should be prescribed with care to patients already on anti-coagulant therapy.6PubMed. Anti-coagulant activity of plants: mini review If you take warfarin, heparin, or one of the newer direct oral anticoagulants, adding lungwort tea or supplements to your routine without telling your doctor could push your blood-thinning effect into a dangerous range and increase your risk of bleeding.
Beyond anticoagulants, the COX-2 inhibition observed in the lab raises a theoretical concern about interactions with NSAIDs. Both the herb and the drug would be hitting the same inflammatory pathway, and while the extract concentrations tested in the lab may not match what reaches your tissues after drinking tea, stacking anti-inflammatory effects is the kind of thing pharmacologists prefer to monitor rather than ignore. The safest approach is simple: if you take any prescription medications, mention lungwort use to your doctor or pharmacist, even if they look at you blankly. Herb-drug interactions are under-studied across the board, and healthcare providers cannot flag a risk they do not know about.
Plant Lungwort Versus Lichen Lungwort
A common source of confusion is that two entirely different organisms share the common name “lungwort.” Pulmonaria officinalis is a flowering plant in the borage family. Lobaria pulmonaria, sometimes called tree lungwort or lung lichen, is a lichen that grows on the bark of old-growth trees in damp forests. Both got their names from the same Doctrine of Signatures reasoning: the lichen’s lobed, pitted surface was thought to resemble lung tissue, just as the plant’s spotted leaves were.
The two organisms have completely different chemistry, different traditional uses, and different ecological roles. Lichens in general produce a range of unique secondary metabolites not found in flowering plants, and Lobaria pulmonaria has been studied for antimicrobial and other bioactivities in the broader context of lichen pharmacology. But the evidence base for tree lungwort is even thinner than for plant lungwort, and any health claim you encounter about “lungwort” should specify which organism is being discussed. Supplements labeled simply as “lungwort” could contain either one, or a mixture, or neither, depending on the supplier’s sourcing and honesty.
How Lungwort Products Are Sold and What to Watch For
You will find lungwort sold as dried loose-leaf herb for teas, as capsules or tablets of powdered herb, as tinctures (alcohol-based extracts), and occasionally as an ingredient in herbal cough syrups or respiratory blends. None of these products have been evaluated or approved by the FDA or the European Medicines Agency for the treatment of any disease. In the United States, they are sold under the Dietary Supplement Health and Education Act framework, which means the manufacturer is responsible for safety and label accuracy, but there is no pre-market approval or independent testing requirement.
Practical things to keep in mind if you decide to try lungwort despite the limited evidence:
- Source transparency: Look for products that identify the species (Pulmonaria officinalis) on the label and ideally name the plant part used (aerial parts, leaves). Vague labeling is a red flag.
- PA testing: Ask or look for a certificate of analysis showing pyrrolizidine alkaloid levels. Reputable herbal companies test for PAs and will share the results. If the company cannot provide this information, consider that a warning sign.
- Dosing: There is no established safe or effective dose for lungwort in humans. Traditional herbalism texts suggest modest amounts of dried herb steeped as tea, but “traditional” dosing reflects custom, not pharmacological optimization.
- Duration: Given the PA concern, long-term daily use is harder to justify than occasional short-term use. A few cups during a cold is a very different exposure profile from drinking it every morning for months.
Pregnancy, Breastfeeding, and Other Vulnerable Groups
Pregnant and breastfeeding women are generally advised to avoid herbal products that lack established safety data, and lungwort falls squarely into that category. The pyrrolizidine alkaloid concern is heightened during pregnancy because PAs can cross the placenta, and the developing fetal liver is less equipped to detoxify them than an adult liver. Children, as the case report from Spain illustrates, can also react strongly to lungwort infusions. People with liver disease should avoid PA-containing herbs entirely, since their already compromised livers are more vulnerable to the cumulative toxic effects.
Anyone scheduled for surgery should stop lungwort use at least two weeks beforehand, given the reported anti-coagulant properties. Excessive bleeding during surgery is a real and preventable risk, and surgeons routinely ask about supplement use for exactly this reason. If your surgeon only asks about prescription medications, volunteer the information about herbal products on your own.
Where the Research Stands and What Would Move the Needle
The research on lungwort as a medicinal plant is stuck in an early phase. The chemistry is well-characterized and genuinely interesting, the in vitro work on antioxidant capacity and COX-2 inhibition is solid within its limitations, and the traditional use history is long enough to suggest the plant is not entirely inert. But there is a canyon between “phenolic-rich extract inhibits an enzyme in a dish” and “lungwort tea helps people with bronchitis recover faster.” Bridging that canyon would require, at minimum, pharmacokinetic studies showing that the active compounds survive digestion and reach target tissues in meaningful concentrations, followed by randomized controlled trials comparing lungwort preparations to placebo for specific conditions.
The reality is that such trials are unlikely to happen soon. Lungwort is not a blockbuster commercial crop, it is not patentable, and there is no pharmaceutical company with an incentive to fund expensive human trials. The research that does exist is driven by academic curiosity about Boraginaceae phytochemistry, not by a coordinated effort to develop lungwort into an approved therapeutic. That is not unique to lungwort; it describes most traditional herbal remedies. The gap between folk reputation and clinical proof is the norm in botanical medicine, not the exception, and readers should calibrate their expectations accordingly.