14 Herbs for Lungs: What the Evidence Actually Supports
By Irene A. Paragas, MD | Medically reviewed | October 2026 | 14 min read
Most lists of herbs for the lungs are interchangeable. The same fourteen or so plants appear in the same order, with the same confident claims and no indication of which ones have ever been tested.
This one is graded. Each herb below is marked by how much human evidence exists, which turns out to vary enormously.
Two of the fourteen have genuine randomised trials behind them. Most have tradition and laboratory work but no clinical testing. One carries a real safety concern that is rarely mentioned.
And there is a second list further down that matters more than the first: herbs that appear on lung-health articles regularly and that you should not take at all. One of them has caused liver failure.
Read This First
Nothing here treats asthma or COPD. No herb on this page is a substitute for an inhaler, and none should delay seeing a clinician about a breathing problem.
That is not a token disclaimer. A survey of 326 adults with persistent asthma found herbal remedy users had markedly lower adherence to their inhaled steroids, with an odds ratio of 0.4.
The risk is usually not the herb itself. It is what the herb quietly replaces.
The 14 Herbs, Graded
The pattern is worth stating plainly. Eleven of the fourteen have essentially no clinical evidence for lung outcomes.
That does not make them useless, and a warm herbal tea genuinely soothes an irritated throat. It does mean the claims attached to them online run far ahead of what anyone has demonstrated.
The Two With Real Trial Evidence
1. Pelargonium sidoides, also sold as umckaloabo
A South African geranium, standardised as the extract EPs 7630. This is the best-studied herb on the list, and the story is instructive.
Placebo-controlled trials looked strong. In one trial of 124 adults with acute bronchitis, 68.8 percent in the extract group showed treatment response versus 33.3 percent on placebo. A meta-analysis of six trials found reduced bronchitis symptom scores by day seven.
Then a pragmatic trial compared it against ordinary care rather than placebo in Swiss primary care. It did not shorten symptom duration. Adverse events were more common in the extract group, 32.3 percent versus 21.5 percent.
The same report noted that at least two trials of this extract in adults remain unpublished, which is the kind of detail that should temper confidence in the pooled positive results.
This is the honest summary for the best-evidenced herb here. It may modestly help cough in acute bronchitis, a condition that resolves by itself in one to three weeks regardless. It did not beat usual care when tested that way, and unpublished trials remain outstanding.
2. Black seed, Nigella sativa
The most interesting entry, because it was tested in asthma rather than a self-limiting infection.
A randomised, double-blind, placebo-controlled trial gave 80 patients 500 mg of black seed oil twice daily for four weeks, against olive oil as placebo. Asthma Control Test scores improved significantly in the treatment group.
The caveats matter though. Changes in actual lung function were not clearly significant, the trial was small and only four weeks long, and a second trial in partly controlled asthma was single-blind with acknowledged limitations.
So this is a promising signal in symptom scores, not established treatment. It is not a reason to reduce asthma medication, and the one thing that would make it dangerous is using it that way.
The Traditional Expectorants
3. Ivy leaf
Widely licensed across Europe as a cough syrup and genuinely popular in German-speaking countries, where it is a pharmacy staple for productive cough.
Regulatory acceptance there rests partly on long-standing traditional use rather than on the kind of trial data that would satisfy a sceptical reviewer. I was not able to locate convincing published trials of ivy leaf on its own.
Low risk at normal doses, and a reasonable thing to try for a chesty cough if you want to try something.
4. Thyme
Contains thymol and has a long history as a cough remedy. Most of the clinical work has tested thyme combined with primrose root rather than thyme alone, which makes the individual contribution hard to isolate.
As a tea or a culinary herb it is entirely safe. Concentrated thyme oil should not be swallowed.
5. Eucalyptus
The active compound is 1,8-cineole, which has been studied in standardised pharmaceutical preparations in Europe for bronchitis and sinus congestion.
Inhaled as steam it reliably makes congestion feel looser. Whether it changes the course of anything is less clear.
Important restrictions. Eucalyptus oil is toxic if swallowed, with small amounts dangerous to children. It should never be applied to the face or near the nostrils of infants or young children, where it can cause breathing difficulty.
6. Peppermint
Menthol triggers cold receptors in the airway lining, which produces a convincing sensation of clearer breathing.
That sensation is not the same as moving more air. Studies on menthol and actual airflow have not shown meaningful change, and in some people with asthma strong menthol vapour is an irritant.
Pleasant and harmless as a tea. Treat the feeling of openness as comfort rather than effect.
7. Mullein
The herb that heads nearly every list of this kind, usually described as a lung tonic.
Pharmacology references are blunter. Reliable clinical data on verbascoside, its main active component, are described as limited and controversial, and safety data in pregnancy are lacking.
The traditional use for cough and bronchial irritation is centuries old. The evidence behind the modern claims is close to absent, and its position at the top of these lists reflects popularity rather than proof.
One practical note. Mullein leaves are covered in fine hairs that irritate the throat, so tea must be strained well through a fine filter.
8. Marshmallow root
Works by a mechanism that is at least easy to understand. It is rich in mucilage, a gel-forming polysaccharide that coats and soothes irritated tissue.
That is a local effect on the throat rather than anything reaching the lungs. For a raw, dry, scratchy cough it is a reasonable and safe comfort measure.
It can slow absorption of medications taken at the same time, so separate them by an hour or two.
9. Licorice root, with a real caveat
Licorice is a traditional cough remedy, and it is also the one herb on this list with documented potential to cause serious harm at ordinary doses.
Glycyrrhizin causes pseudoaldosteronism, a condition that raises blood pressure and drives potassium down. The case literature is substantial, including hypokalaemia from licorice tea, from licorice cough syrup taken by self-medication, and one case in an elderly patient where respiratory failure with diaphragmatic dysfunction was reported.
Avoid it, or use only deglycyrrhizinated licorice, if you have high blood pressure, heart or kidney disease, low potassium, or take diuretics, digoxin or corticosteroids. Also avoid in pregnancy.
Occasional licorice tea in a healthy adult is a different matter from daily use of concentrated extract. The dose and the duration are what turn this from a mild herb into a clinical problem.
The Ones Included Mostly by Reputation
10. Ginger
Genuine anti-inflammatory activity in laboratory work and decent evidence for nausea. Nothing demonstrating benefit for lung function or respiratory outcomes in people.
Warm, soothing, safe. Included on lung lists because it is anti-inflammatory in general, which is not the same as acting on airways.
11. Turmeric
Curcumin suppresses inflammatory pathways convincingly in cell and animal studies, including airway models.
The obstacle is that oral curcumin is poorly absorbed, and the human respiratory trials have not been done. Promising mechanism, absent clinical evidence.
12. Oregano
Oregano oil has antimicrobial activity in a dish. That has not been shown to translate into treating respiratory infections in people, and concentrated oregano oil is a mucosal irritant.
Excellent on food. Not a demonstrated respiratory treatment.
13. Plantain leaf
The common lawn weed, not the banana. Mucilaginous like marshmallow root, with a similar soothing rationale and similarly thin clinical evidence.
14. Elecampane
A traditional European expectorant containing inulin and sesquiterpene lactones. Very little human data, and the lactones can cause allergic reactions in people sensitive to the daisy family, which includes ragweed and chamomile.
Herbs on These Lists You Should Not Take
This section is the reason to be careful with lung-herb articles generally. The following appear on them regularly, and all four carry documented harm.
Two details deserve emphasis.
Coltsfoot’s traditional indication is cough. That is precisely why it turns up on lung-herb lists, and precisely why its pyrrolizidine alkaloid content is worth knowing about. A review counted nine cases of definite liver toxicity attributable to chaparral alone, plus six possible cases.
And lobelia is marketed for asthma. An herb sold for the condition, with documented reactions at small doses, taken by people who may be using it in place of an inhaler, is the most concerning combination on this page.
What Actually Improves Lung Health
None of this is as interesting as a list of plants, which is probably why it gets less attention.
- Stopping smoking is the single largest intervention available, and lung function decline slows measurably after quitting. Nothing herbal comes within range of it.
- Using prescribed inhalers correctly. Inhaler technique is wrong in a large proportion of patients, and fixing it costs nothing.
- Vaccination against influenza, pneumococcus, COVID and RSV where eligible, since infections drive much of the long-term damage in chronic lung disease.
- Pulmonary rehabilitation if you have COPD. This has strong trial support for breathlessness and exercise capacity, and is underused.
- Aerobic exercise, which improves breathlessness and function even where it does not change spirometry numbers.
- Indoor air quality. Ventilation while cooking, addressing damp and mould, and avoiding wood smoke and solvent fumes.
- Diet quality. See our piece on 14 foods for healthy lungs and improved breathing, where the cohort evidence is stronger than anything on this page.
- Getting a diagnosis. Breathlessness is not one condition. Asthma, COPD, heart failure, anaemia and anxiety all cause it and are managed completely differently.
See a Doctor Rather Than Trying Herbs If You Have
Coughing up blood, any amount, or a cough lasting more than three weeks.
Breathlessness that is new, worsening, or comes on at rest or when lying flat.
Chest pain, fever with breathlessness, or unexplained weight loss.
Increasing reliance on a reliever inhaler, which indicates asthma that is not controlled and needs review, not supplementation.
Wheeze or breathlessness that wakes you at night.
Frequently Asked Questions
What is the best herb for lungs?
On trial evidence, Pelargonium sidoides has the most research behind it for acute bronchitis, though a pragmatic trial found it no better than usual care. For asthma symptoms specifically, black seed has small positive trials. Everything else on the list rests on tradition rather than testing.
Can herbs clean or detox your lungs?
No. Lungs clear themselves continuously through the mucociliary escalator, a layer of mucus moved upward by beating cilia. No herb, tea or supplement accelerates this, and the idea of a lung detox has no physiological basis.
Will herbs repair lungs after smoking?
Some recovery happens on its own after quitting, and the rate of lung function decline slows. No herb has been shown to add to that or to reverse established emphysema. Quitting is the intervention that works.
Is mullein tea good for the lungs?
It is a traditional remedy for cough and it is low risk, but reliable clinical data on its main active compound are described as limited and controversial. Strain it carefully, since the leaf hairs irritate the throat.
Can I take these with my asthma inhaler?
Most of these herbs have no known interaction with inhaled medication, but the key point is that herbs are an addition and never a replacement. Tell your clinician what you are taking, particularly licorice, which interacts with corticosteroids and diuretics.
Are herbs safer than medication?
Not inherently. The four herbs in the red table above carry documented risks of liver failure or cardiovascular collapse, and herbal products are not tested for potency or purity the way licensed medicines are. Natural describes origin, not safety.
Does steam inhalation with herbs help?
Steam itself can make congestion feel looser and is generally harmless if the water is not boiling. Added eucalyptus or peppermint may make it feel more effective. Keep it away from young children, and never leave hot water where a child could reach it.
What about herbs for COPD?
No herb has established benefit in COPD. Pulmonary rehabilitation, smoking cessation, correct inhaler use and vaccination all have real evidence, and pulmonary rehabilitation in particular is both effective and widely underused.
The Bottom Line
Of fourteen herbs commonly recommended for the lungs, two have meaningful human trials, and even the best of those failed to beat ordinary care when tested pragmatically.
Most of the rest are safe, mildly soothing, and far less powerful than the claims attached to them. Several are pleasant to drink and there is no reason to avoid them.
The more useful takeaway is the one the usual version of this article leaves out. Four herbs that routinely appear on these lists have caused documented liver failure or cardiovascular harm, and one of them is sold specifically for asthma.
If you have a breathing problem, the things that change outcomes are unglamorous and well established. Stop smoking, use your inhaler properly, get vaccinated, do the rehabilitation programme if offered, and get a diagnosis for breathlessness rather than a remedy for it.
Herbs can sit alongside that. The harm comes when they sit instead of it.
References
- Treatment of acute bronchitis in adults with a Pelargonium sidoides preparation (EPs 7630): a randomized, double-blind, placebo-controlled trial. PubMed.
- Pelargonium sidoides extract (EPs 7630) versus usual care for acute bronchitis in Swiss primary care (PHYTOBRONCH): a pragmatic, open-label, randomised controlled trial. PMC.
- Pelargonium sidoides for acute bronchitis: a systematic review and meta-analysis. Phytomedicine.
- Effects of Pelargonium sidoides extract EPs 7630 on acute cough and quality of life. PMC.
- Nigella sativa as an anti-inflammatory agent in asthma. BMC Research Notes.
- Use of herbal remedies and adherence to inhaled corticosteroids among inner-city asthmatic patients. PubMed.
- Comfrey. LiverTox: Clinical and Research Information on Drug-Induced Liver Injury. NIH.
- Coltsfoot: hepatotoxic pyrrolizidine alkaloids, side effects and precautions. RxList.
- Chaparral. Memorial Sloan Kettering Cancer Center, About Herbs database.
- Dietary Supplements: A Framework for Evaluating Safety. National Academies Press. Chaparral hepatotoxicity case counts.
- Dangerous supplements. Consumer Reports. Lobelia adverse event reporting.
- Case report: severe respiratory failure caused by licorice. PMC.
- Pseudo-hyperaldosteronism arising from licorice cough syrup self-ingestion: a case report. PMC.
- Mullein: uses, benefits and dosage. Drugs.com natural products database.
Medical disclaimer. This article is for informational and educational purposes only and is not medical advice. No herb described here is a treatment for asthma, COPD, pneumonia, bronchiectasis or any other lung disease, and nothing on this page should be used in place of prescribed medication. Never reduce or stop an inhaler, steroid or other prescribed treatment without speaking to your clinician. Herbal products are not regulated for potency or purity in the same way as licensed medicines, and dosing, contamination and adulteration are documented problems. Tell your doctor and pharmacist about any herb or supplement you take, as interactions with prescription medication are common. Licorice can raise blood pressure and lower potassium and should be avoided by anyone with hypertension, heart disease, kidney disease or low potassium, in pregnancy, or alongside diuretics, digoxin or corticosteroids. Eucalyptus oil is toxic if swallowed and must not be applied near the face of infants or young children. Seek medical attention for coughing up blood, a cough lasting more than three weeks, new or worsening breathlessness, chest pain, fever with breathlessness, unexplained weight loss, or increasing reliever inhaler use.
Editorial note. Evidence grades reflect published human studies located at the time of writing, not traditional reputation. Where we could not verify trial data for an herb, including ivy leaf as a single agent, we have said so rather than implying evidence exists. The Pelargonium entry deliberately reports both the positive placebo-controlled results and the null pragmatic trial, along with the authors’ note that at least two trials remain unpublished. Black seed trial results concern symptom control scores, with changes in lung function not clearly significant. The association between herbal use and lower inhaled steroid adherence is cross-sectional and does not establish causation. Safety information on comfrey, coltsfoot, chaparral and lobelia draws on regulatory actions and case literature, some of it dating from the 1990s and 2000s; readers should verify current regulatory status directly, as it varies by country and may have changed.