Limited evidenceImmunity

Hyssop

A Mediterranean mint-family herb with a long tradition in cough and cold remedies. There is essentially no clinical research behind that use; the only controlled trial is a small one in asthma.

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What the science says

No trials for coughs or colds Limited evidence
Despite centuries of traditional use for respiratory complaints, no controlled trial of hyssop for cough, colds or influenza is indexed in PubMed. A 2022 review of Hyssopus essential oil found only laboratory work on antimicrobial and antioxidant activity, with no human efficacy data.
One small asthma trial Limited evidence
A randomized, double-blind, placebo-controlled trial of hyssop syrup in mild to moderate asthma reported improvement in symptom scores. It is a single small trial in a different condition from the one hyssop is usually sold for, and it has not been replicated.

Dosage & safety

Studied doseNo dose has been established. Traditional use is 1–2 g of dried herb as an infusion, two to three times a day; commercial syrups follow their own label.

SafetyThe essential oil contains pinocamphone, which is convulsant at high doses — the oil should not be taken internally, and people with epilepsy should avoid hyssop preparations entirely. Avoid in pregnancy. Not enough data to judge long-term use.

How to take it

TimingTiming does not matter; traditional use is two to three times a day.

With food?Either way.

Worth knowingUse the dried herb as an infusion and never the essential oil internally — the convulsant risk sits in the concentrated oil, not the tea.

Interactions

With medications

antiepileptic medication
Pinocamphone in hyssop is convulsant at higher exposures and can work against seizure control. avoid hyssop preparations entirely if you have epilepsy or take these drugs

Well-established interactions only — this is not a complete list. Always tell your doctor and pharmacist what you take.

Frequently asked questions

Does hyssop work for coughs and colds?

There is no good evidence that hyssop helps coughs or colds; the grade is limited. No controlled trial of hyssop for cough, colds or influenza exists, and the laboratory antimicrobial work on hyssop oil has no human efficacy data behind it.

Is hyssop good for asthma?

One small randomized, placebo-controlled trial of hyssop syrup in mild to moderate asthma reported better symptom scores, but it has never been replicated, so the evidence for hyssop in asthma is limited.

Is hyssop essential oil safe to take internally?

No. Hyssop essential oil contains pinocamphone, which is convulsant at high doses, so the oil should never be swallowed; use the dried herb as a tea instead.

Can I take hyssop if I have epilepsy or am pregnant?

No. People with epilepsy or on antiepileptic medication should avoid hyssop preparations entirely because pinocamphone can work against seizure control, and hyssop should also be avoided in pregnancy.

Scientific references

Effect of Hyssop (Hyssopus officinalis) Syrup on Mild to Moderate Asthma: A Randomized Double-Blind Placebo-Controlled Trial
Daneshfard B, Amini F, Jaladat AM, Momeni B, Abdolahinia A, Hosseinkhani A, Hosseini L — Tanaffos, 2024
Hyssopus Essential Oil: An Update of Its Phytochemistry, Biological Activities, and Safety Profile
Sharifi-Rad J, Quispe C, Kumar M, Akram M, Amin M, Iqbal M, Koirala N, Sytar O, Kregiel D, Nicola S, Ertani A, Victoriano M, Khosravi-Dehaghi N, Martorell M, Alshehri MM, Butnariu M, Pentea M, Rotariu LS, Calina D, Cruz-Martins N, Cho WC — Oxid Med Cell Longev, 2022

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Herbal medicines: what the evidence says (335)