Bronchitis

Overview

Three supplements are indexed for bronchitis across 11 studies.

N-Acetyl Cysteine (NAC) (WA 72; medium effect size, high evidence, very high trust) has the strongest evidence: inhaled NAC is FDA-approved for acute bronchitis, and oral NAC at 400–1500 mg daily for several months may reduce chronic bronchitis flare-ups, with about 61% reporting symptom improvement versus 34% on placebo. Eucalyptus in the standardized Myrtol product (WA 44) reduced flare-ups in chronic bronchitis and improved acute symptoms in small trials.

Panax Ginseng (WA 44; low effect size, low evidence, medium trust) has unclear benefit from one small antibiotic combination study. See the heatmap and evidence reviews below for full detail.

Effect graph

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Relevant supplements

Relevant supplements sorted by DEX Score.


N-Acetyl Cysteine (NAC)	★★★★★	Medium
Vitamin C	★★★★★	Low
Panax Ginseng	★★★★★	Low
Eucalyptus	★★★★★	Low

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Studies

Find individual evidence reviews for supplements sorted by DEX Score.

4 supplements for and rated at least stars. All purchase bands. No minimum star filter.

N-Acetyl Cysteine (NAC)View supplement →

Consider purchase★★★★★

How we scored this

Effect SizeMediumEvidenceHighTrustVery High

Evidence Review

N-acetyl cysteine (NAC) inhaled is FDA-approved to treat acute bronchitis.
Taking NAC by mouth, typically 400-1500 mg daily, may reduce flare-ups and improve symptoms of chronic bronchitis when used for several months.
Around 61% of people taking NAC had symptom improvements, compared to 34% taking placebo.
Shorter treatment durations with NAC by mouth are less effective for chronic bronchitis.

Browse 8 studies3 meta-analyses

MetaEffect of Orally Administered N-Acetylcysteine on Chronic Bronchitis: A Meta-analysis2019n=775

A meta-analysis of 775 chronic bronchitis patients found oral NAC reduced exacerbation frequency and improved symptoms versus control.

Effect: Benefit
Dose: 1200 mg/day
Population: Chronic bronchitis patients
Participants: 775

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RCTN-acetylcysteine improves the clinical conditions of mustard gas-exposed patients with normal pulmonary function test2008n=40

A 4-month RCT of 40 mustard gas-exposed patients found 1200 mg/day NAC improved pulmonary symptoms and FEV1 versus baseline.

Effect: Benefit
Duration: 4 months
Dose: 1200 mg/day
Population: Children
Participants: 40

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RCTTherapeutics effect of N-acetyl cysteine on mustard gas exposed patients: evaluating clinical aspect in patients with impaired pulmonary function test2008n=72

An RCT of 72 mustard gas-exposed patients found 1800 mg/day NAC improved clinical pulmonary conditions and quality of life.

Effect: Benefit
Duration: 4 months
Dose: 1800 mg/day
Population: Children
Participants: 72

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MetaEfficacy of oral long-term N-acetylcysteine in chronic bronchopulmonary disease: a meta-analysis of published double-blind, placebo-controlled clinical trials2000

A meta-analysis found long-term oral NAC (400 mg/day) reduced COPD exacerbations and improved lung function in chronic bronchopulmonary disease.

Effect: Benefit
Dose: 400 mg/day
Population: ALL patients

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MetaThe effect of oral N-acetylcysteine in chronic bronchitis: a quantitative systematic review2000

A quantitative meta-analysis found oral NAC significantly reduced chronic bronchitis symptoms and exacerbation rates across trials.

Effect: Benefit
Duration: 12–24 weeks
Population: ALL patients

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RCTEffect of oral N-acetylcysteine on mucus clearance1985

A 4-week RCT found oral NAC (200 mg/day) improved mucus clearance in patients with chronic bronchitis versus placebo.

Effect: No Benefit
Duration: 4 weeks
Dose: 200 mg/day
Population: Chronic bronchitis patients

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Clinical trial[Multicenter, double-blind study of oral acetylcysteine vs. placebo]1980n=215

A multicenter double-blind study of 215 patients found oral acetylcysteine improved respiratory symptoms versus placebo over 7 days.

Effect: Benefit
Duration: 7 days
Dose: 1.5 g/day
Population: Bronchitis patients
Participants: 215

View on PubMed

Controlled trialA controlled study of the safety and efficacy of acetylcysteine-isoproterenol combination1970

A controlled study found acetylcysteine-isoproterenol combination was safe and effective for bronchial secretion management.

Effect: Benefit

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EucalyptusView supplement →

Reconsider purchase★★★★★

How we scored this

Effect SizeLowEvidenceLowTrustMedium

Evidence Review

In people with chronic bronchitis, taking 900 mg daily of a product called Myrtol, which contains eucalyptus and pine and lime extracts, for at least one month lowered flare-ups by 72%, compared with 53% for placebo.
For acute bronchitis, taking 1200 mg daily of the same product for 14 days helped nearly all patients improve, compared to only 32% in those taking placebo.
This suggests that a standardized product containing eucalyptus oil can be a helpful and safe treatment for bronchitis.

Browse 2 studies

RCTEfficacy and tolerability of myrtol standardized in acute bronchitis. A multi-centre, randomised, double-blind, placebo-controlled parallel group clinical trial vs. cefuroxime and ambroxol2000n=172

In 676 adults with acute bronchitis over 2 weeks, myrtol standardized (1,200 mg/day) achieved 92.9% responder rate at week 1 versus 77.3% placebo (p < 0.001), comparable to cefuroxime and ambroxol.

Effect: Benefit
Duration: 2 weeks
Dose: 200 mg/day
Population: Adults
Participants: 172
Ages: ≥18

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RCTEfficacy and tolerability of myrtol standardized in long-term treatment of chronic bronchitis. A double-blind, placebo-controlled study. Study Group Investigators1999n=246

In 246 chronic bronchitis patients over 6 months, myrtol standardized (900 mg/day) significantly reduced exacerbation rate, antibiotic need, and cough-related health impairment versus placebo.

Effect: Benefit
Duration: 6 months
Dose: 900 mg/day
Population: Chronic bronchitis patients
Participants: 246

View on PubMed

Panax GinsengView supplement →

Reconsider purchase★★★★★

How we scored this

Effect SizeLowEvidenceLowTrustMedium

Evidence Review

It is not clear if taking Panax ginseng helps bronchitis.
One small study suggests that taking a special ginseng extract twice daily for 9 days along with antibiotics might reduce bacteria in the airways more than antibiotics alone.

Browse 1 study

RCTEffects of the Standardised Ginseng Extract G115 in Patients with Chronic Bronchitis: A Nonblinded, Randomised, Comparative Pilot Study2001

An RCT of standardized ginseng extract G115 in chronic bronchitis patients was listed without an abstract in the batch record.

Effect: Benefit
Population: Patients with Chronic Bronchitis

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Vitamin CView supplement →

Reconsider purchase★★★★★

How we scored this

Effect SizeLowEvidenceLowTrustMedium

Evidence Review

Taking vitamin C by mouth does not help with symptoms or shorten recovery from acute bronchitis.
Studies show a short course of vitamin C is no better than standard treatment for improving how people feel or for speeding up recovery.

Browse 1 study

RCTAzithromycin for acute bronchitis: a randomised, double-blind, controlled trial2002n=112

An RCT in 220 adults with acute bronchitis found 5-day azithromycin was no better than low-dose vitamin C (1.5 g total) for symptom recovery or return to usual activities by day 7.

Effect: Benefit
Duration: 5 days
Dose: 1.5 g/day
Population: Adults
Participants: 112

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Evidence visualised

Same ratings as above, aggregated so you can see coverage and imbalance.

Purchase-guidance distribution

How many supplements fall in each purchase band

Effect-size distribution

How large the reported benefits tend to be

Study distribution across 4 supplements for bronchitis (12 studies total).
Supplement	DEX	Studies	Meta-analyses	Share
N-Acetyl Cysteine (NAC)	★★★★★72%	8	3	67%
Eucalyptus	★★★★★44%	2	0	17%
Panax Ginseng	★★★★★44%	1	0	8%
Vitamin C	★★★★★44%	1	0	8%

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Overview

Effect graph

Relevant supplements

Studies

Evidence visualised

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