Moderate evidenceImmunity

Thyme Extract

Thyme is the best-studied cough herb in Europe, with several placebo-controlled trials in acute bronchitis. The catch is that every positive trial used thyme combined with ivy leaf or primrose root, never thyme on its own.

Evidence last reviewed: August 2026

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What the science says

Faster resolution of acute bronchitis Moderate evidence
A double-blind, placebo-controlled trial in adults with acute bronchitis and productive cough found that a thyme herb and ivy leaf fluid extract reduced coughing fits substantially more than placebo over the treatment period. Two further placebo-controlled trials of thyme with primrose root reported the same direction of effect.
Thyme alone has not been tested Limited evidence
The trials evaluated fixed combinations, so the contribution of thyme by itself is unknown. A single-ingredient thyme extract cannot be assumed to reproduce those results.
Antimicrobial claims are laboratory-level Limited evidence
Thymol and carvacrol kill bacteria in culture, but the bronchitis trials measured cough and symptom scores, not infection clearance. There is no clinical evidence that thyme acts as an antibiotic in humans.

Dosage & safety

Studied doseThe trials used fluid or dry extract combinations dosed three times daily per product label. As a standalone, 1–2 g of dried thyme as an infusion up to three times daily is the traditional amount.

SafetyWell tolerated; the commonest complaints in the trials were mild gastrointestinal upset. Avoid if allergic to mint-family plants. Thyme essential oil is not interchangeable with the extract and should not be swallowed undiluted. Limited data in pregnancy and in children under one year.

Scientific references

Efficacy and tolerability of a fluid extract combination of thyme herb and ivy leaves and matched placebo in adults suffering from acute bronchitis with productive cough. A prospective, double-blind, placebo-controlled clinical trial
Kemmerich B, Eberhardt R, Stammer H — Arzneimittelforschung, 2006
Evaluation of efficacy and tolerability of a fixed combination of dry extracts of thyme herb and primrose root in adults suffering from acute bronchitis with productive cough. A prospective, double-blind, placebo-controlled multicentre clinical trial
Kemmerich B — Arzneimittelforschung, 2007
Efficacy and tolerability of a fixed combination of thyme and primrose root in patients with acute bronchitis. A double-blind, randomized, placebo-controlled clinical trial
Gruenwald J, Graubaum HJ, Busch R — Arzneimittelforschung, 2005

Where to buy

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