Supplement analysis backed by scientific evidence · PT

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Limited evidenceImmunity

Houttuynia Cordata

A pungent herb eaten as a vegetable and used medicinally across East Asia, with a strong laboratory record for antiviral and anti-inflammatory activity. Clinical evidence for colds and flu is missing.

Evidence last reviewed: August 2026

What the science says

  • Broad preclinical activity, no infection trials Limited evidence

    An ethnopharmacological review documented antiviral, antibacterial and anti-inflammatory effects across many cell and animal studies, alongside a near-total absence of controlled clinical trials for respiratory infection.

  • One trial, in allergic rhinitis rather than colds Limited evidence

    A randomized trial of a Houttuynia-based Chinese herbal formula reported improved allergic rhinitis symptoms. It tested a multi-herb formula in an allergic condition, so it does not support Houttuynia alone for viral infection.

Dosage & safety

Studied doseNo supplement dose is established. Traditional use is 15–30 g fresh herb or 5–10 g dried in decoction; capsule products follow their own labels.
SafetyOral use as food and tea has a long record of tolerability, with gastrointestinal upset the main complaint. Injectable Houttuynia preparations used in China were associated with serious allergic reactions and were restricted — that risk relates to injections, not oral use, but it signals real allergenic potential. Avoid in pregnancy; data in children are lacking.

Scientific references

Where to buy

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