Limited evidenceImmunity

Forsythia (Lian Qiao)

A core cooling herb in Chinese medicine for sore throat and fever. It has never been tested alone in a clinical trial — all human data come from multi-herb formulas in which forsythia is one ingredient among a dozen.

Where to buy

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What the science says

Studied only inside multi-herb formulas Limited evidence
Forsythia is one of more than ten ingredients in Lianhua Qingwen. A meta-analysis of randomized trials in COVID-19 reported improvements in symptom resolution rates with the formula, but nothing in that data can be attributed to forsythia specifically, and the included trials were mostly open-label and conducted in China.
Antiviral effects are cell-culture level Limited evidence
Forsythoside A isolated from Forsythia suspensa reduced influenza A virus M1 protein in infected cells. In-vitro antiviral activity of an isolated compound does not establish that swallowing the herb affects a real infection.

Dosage & safety

Studied doseNo supplement dose has been validated. Traditional decoction use is 6–15 g of dried fruit per day, usually within a formula.

SafetyMild gastrointestinal upset and loose stools are the commonest complaints. Traditionally avoided in people with weak digestion or chronic diarrhoea. Not studied in pregnancy. Multi-herb Chinese formulas vary widely in composition and quality — buy only from manufacturers that publish testing.

How to take it

TimingTiming does not matter.

With food?With food if it loosens your stools, which is the usual complaint.

Worth knowingIt is almost never used alone in practice — the traditional evidence is for multi-herb formulas, so a single-herb capsule is not the thing that was used.

Frequently asked questions

Does forsythia (lian qiao) work for sore throat or colds?

The evidence for forsythia is limited: it has never been tested alone in a clinical trial. Human data come only from multi-herb formulas such as Lianhua Qingwen, where any effect cannot be attributed to forsythia.

Is forsythia antiviral?

Only in cell culture. Forsythoside A isolated from forsythia reduced an influenza A protein in infected cells, but that does not show that taking the herb affects a real infection.

How much forsythia should I take?

No supplement dose of forsythia has been validated. Traditional decoction use is 6–15 g of dried fruit per day, usually as part of a formula rather than alone.

Does forsythia have side effects?

Mild stomach upset and loose stools are the most common complaints with forsythia, and it is traditionally avoided if you have weak digestion or chronic diarrhoea. It has not been studied in pregnancy.

Scientific references

Traditional Chinese medicine Lianhua Qingwen treating corona virus disease 2019(COVID-19): Meta-analysis of randomized controlled trials
Zeng M, Li L, Wu Z — PLoS One, 2020
Antiviral effect of forsythoside A from Forsythia suspensa (Thunb.) Vahl fruit against influenza A virus through reduction of viral M1 protein
Law AH, Yang CL, Lau AS, Chan GC — J Ethnopharmacol, 2017

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Herbal medicines: what the evidence says (335)