Moderate evidenceImmunity

Herbal Cough Syrups

Syrups built on ivy leaf, thyme and honey. The evidence is better than for most herbal categories, though the effects are small and the trials are largely manufacturer-funded.

Evidence last reviewed: August 2026

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What the science says

Thyme and ivy for acute bronchitis Moderate evidence
A prospective double-blind placebo-controlled trial in 361 adults with acute bronchitis and productive cough found a thyme-ivy fluid extract reduced coughing fits faster than placebo, with about a two-day advantage in reaching a 50% reduction.
Ivy leaf across respiratory infections Limited evidence
An updated systematic review of ivy leaf for acute upper respiratory tract infections found consistently positive but methodologically weak evidence, dominated by open-label and manufacturer-sponsored studies, and concluded that firm efficacy claims are not yet justified.
Honey for acute cough in children Moderate evidence
A Cochrane review found honey probably reduces cough frequency and severity in children more than no treatment or placebo, and performs about as well as dextromethorphan. The certainty of evidence was rated moderate to low.

Dosage & safety

Studied doseThe thyme-ivy trial used 5.4 mL of fluid extract three times daily for 11 days. Ivy-only syrups typically supply 35 mg of dry extract two to three times daily for adults. Honey trials used roughly 2.5-10 mL as a single evening dose in children.

SafetyDo not give honey to infants under 12 months because of the risk of infant botulism. Ivy leaf can cause nausea, vomiting or diarrhoea, and allergic reactions occur. Many syrups contain alcohol or large amounts of sugar; check the label if you have diabetes or are giving it to a child. Cough lasting more than three weeks, or with fever, breathlessness or blood, needs medical assessment rather than a syrup.

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
Ivy leaf (Hedera helix) for acute upper respiratory tract infections: an updated systematic review
Sierocinski E, Holzinger F, Chenot JF — Eur J Clin Pharmacol, 2021
Honey for acute cough in children
Oduwole O, Udoh EE, Oyo-Ita A — Cochrane Database Syst Rev, 2018

Where to buy

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