Limited evidenceImmunity

Lomatium Dissectum

A root used by Indigenous peoples of the American West and marketed as a natural antiviral. There are no human trials at all, and the best-documented human effect in the literature is a whole-body rash.

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What the science says

Antiviral activity Limited evidence
An ethnopharmacological screening study of British Columbian medicinal plants found antiviral activity in cell culture for several species including Lomatium. Nothing has been tested in people.
Characteristic rash Limited evidence
The most consistent human observation is a diffuse measles-like rash after ingestion, described in a published case report and in older ethnobotanical accounts of the plant's water-soluble constituents.

Dosage & safety

Studied doseNo studied dose exists. Tinctures are typically labelled at 10–30 drops up to three times daily, which reflects tradition rather than evidence.

SafetyA widespread itchy rash is a well-documented reaction and can appear days into use. Avoid in pregnancy and breastfeeding and in anyone taking immune-modulating drugs; there are no formal toxicity studies.

How to take it

TimingTiming does not matter.

With food?Either way.

Worth knowingStop at the first sign of a rash — the characteristic lomatium reaction is a widespread itchy eruption that can start days into a course and takes weeks to settle.

Interactions

With medications

immune-modulating drugs and immunosuppressants
It is used as an immune stimulant and has no toxicity studies, so combining it with immune therapy is unpredictable. avoid the combination

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

Frequently asked questions

Is lomatium dissectum an effective antiviral?

There are no human trials of lomatium at all, so its antiviral claim is limited to cell-culture screening. Nothing has been tested in people.

Does lomatium cause a rash?

Yes. The best-documented human effect of lomatium is a widespread, itchy, measles-like rash that can appear days into use and take weeks to settle, so stop at the first sign of it.

How much lomatium tincture should I take?

No studied dose of lomatium exists; tinctures are typically labelled at 10–30 drops up to three times daily, which reflects tradition rather than evidence.

Who should avoid lomatium?

Avoid lomatium in pregnancy and breastfeeding and if you take immune-modulating drugs or immunosuppressants. There are no formal toxicity studies of lomatium.

Scientific references

Antiviral screening of British Columbian medicinal plants
McCutcheon AR, Roberts TE, Gibbons E — J Ethnopharmacol, 1995
Worse than the Disease? The Rash of Lomatium Dissectum
Marshall KD, Thornton SL — Kans J Med, 2018
Native American food and medicinal plants, 8. Water-soluble constituents of Lomatium dissectum
VanWagenen BC, Huddleston J, Cardellina JH 2nd — J Nat Prod, 1988

Related in Immunity

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Herbal medicines: what the evidence says (335)