Open Source Apothecary At Home / Breathing and airways

Asthma: the herbs are adjuncts and the inhaler is the treatment

Asthma kills people who reduce their preventer inhaler. Nothing on this page is a substitute for it.

safety

Asthma is a chronic inflammatory airway disease in which the treatment — an inhaled corticosteroid preventer, plus a reliever, plus a written action plan — reduces attacks, hospital admissions and deaths. This page's most important function is to say that no herb on it is a substitute for that.

Vitamin D. Low vitamin D is associated with worse asthma control, and supplementation in deficient people has shown a reduction in exacerbations in some meta-analyses, particularly in people who were deficient. This is the most defensible adjunct here, and it is a correction of a deficiency rather than a treatment.

Herbal asthma preparations. Several have small trials: butterbur (with its pyrrolizidine alkaloid problem), Boswellia, Petasites, and various Chinese herbal formulas. The trials are small, blinding is difficult, and none approaches the effect size of an inhaled steroid. There is also a real hazard: some herbal preparations marketed for asthma have contained undeclared corticosteroids or other drugs.

Vitamin D for respiratory infection. There is an association between low vitamin D and respiratory infections, and supplementation shows a modest reduction in infection in deficient people. It is not a general cold preventive.

What actually manages asthma. A preventer inhaler taken regularly even when well; a reliever for symptoms; a written action plan with clear thresholds; correct inhaler technique (which is wrong in a large share of people and is worth checking); trigger identification; and vaccination. A peak-flow meter and a diary turn the management from guesswork into measurement.

The specific danger to name. Steroid tablets bought from an unregulated source, and "herbal" asthma products containing undeclared steroids, are both a route to harm — the first to uncontrolled asthma while the person believes they are covered, the second to steroid side effects nobody is monitoring. If a herbal asthma product works dramatically, suspect an undeclared drug.

What the studies found

Preparation

The treatment — this is not optional

• Take the preventer inhaler as prescribed, even when you feel well. It is the thing that reduces attacks.
• Check your inhaler technique with a pharmacist or nurse. It is wrong in a large share of people and it is free to fix.
• A written action plan with a peak-flow threshold for when to increase treatment and when to seek help
• Carry the reliever; know how many puffs and when to escalate

Vitamin D

• Correct a documented deficiency; 600-800 IU daily is the usual adult intake
• The exacerbation benefit is seen mainly in deficient people

Butterbur and other herbs

• Only a certified PA-free butterbur extract, if at all — the plant contains hepatotoxic pyrrolizidine alkaloids
• Small trials only; no herb matches an inhaled steroid
• If a herbal asthma product produces a dramatic improvement, suspect an undeclared corticosteroid. This is a documented problem.

Breathing exercises

• Buteyko and other breathing retraining have trials showing improved symptoms and reduced reliever use, without improving lung function
• Useful as an adjunct; not a replacement

Adjunct measures

• Trigger identification with a diary — dust mite, pets, pollen, cold air, exercise, smoke, mould
• Vaccination as advised
• Stop smoking, and avoid second-hand smoke
• Saline nasal irrigation if there is coexisting rhinitis

Cautions and interactions

• Never stop or reduce a preventer inhaler because an adjunct is helping. This is the scenario that causes fatal asthma attacks.
• Butterbur contains hepatotoxic pyrrolizidine alkaloids. Only PA-free certified extracts.
• Undeclared corticosteroids in herbal asthma products are a documented problem.
• Do not use oral decongestants or sedating antihistamines without advice.
• Vitamin D: do not mega-dose. Correct a deficiency.

When this is not a self-care problem — get help

• A severe attack: unable to speak in full sentences, using the reliever every few minutes with no relief, a blue tinge to the lips, drowsiness, or a silent chest — emergency services immediately. Do not drive yourself.
• Needing the reliever more than 2-3 times a week — the asthma is not controlled. See a clinician, do not wait.
• Waking at night with asthma symptoms — uncontrolled; assessment.

Known interactions

• Beta-blocker drugs (including eye drops) can worsen asthma. Discuss with a prescriber.
• NSAIDs can trigger attacks in aspirin-sensitive asthma.

Related

• Hay fever and allergic rhinitis
• Coughs and colds: honey, zinc, and the honest list
• Vitamin D: the supplement, the sun, and the U-curve
• Herb-drug interactions: the ones with numbers behind them

Sources

1. Vitamin D supplementation to prevent acute respiratory infections: systematic review and meta-analysis of stratified aggregate data. The lancet. Diabetes & endocrinology 2025; doi:10.1002/9781119536604 PubMed 39993397
2. Vitamin D supplementation decrease asthma exacerbations in children: a systematic review and meta-analysis of randomized controlled trials. Annals of medicine 2024; doi:10.1111/j.1365-2567.2011.03482.x PubMed 39421966
3. Vitamin D for the management of asthma. The Cochrane database of systematic reviews 2023; doi:10.1002/14651858.CD011511.pub2 PubMed 36744416
4. Vitamin D Supplementation and Allergic Diseases during Childhood: A Systematic Review and Meta-Analysis. Nutrients 2022; doi:10.1016/j.nut.2016.01.023 PubMed 36235600
5. Vitamin D can safely reduce asthma exacerbations among corticosteroid-using children and adults with asthma: a systematic review and meta-analysis of randomized controlled trials. Nutrition research (New York, N.Y.) 2021; doi:10.1016/j.nutres.2021.05.010 PubMed 34274554