Lomatium dissectum

botanical
Best with a meal

What is it

Lomatium dissectum is a North American flowering plant in the carrot family, traditionally used by Indigenous peoples and naturopaths as an antiviral and immune-support herb.

Evidence for 1 use

AI-assisted evidence assessment — talk to your doctor before relying on any single supplement.

Viral upper respiratory infection (traditional use)

Mixed

No human clinical trials. Traditional and anecdotal use only.

How it works

The root contains coumarins (suksdorfin), tetronic acids, and resinous compounds with in vitro antiviral and antimicrobial activity. Historic use during the 1917 influenza pandemic among Indigenous Nevadan populations is cited in herbal literature, though contemporary clinical data are essentially absent. Resin fractions appear to be responsible for both purported activity and the most notorious side effect, a measles-like rash. Resin-free preparations are now common.

Dosage

No RDA or evidence-based dose. Traditional tincture dosing is 10-30 drops three times daily; capsules use 250-500 mg of root or extract.

When and how to take it

WHEN: Any time of day. HOW: Take with food to minimize gastric upset.

2 commercial forms

Whole-root tincture

Alcohol extraction captures resins and coumarins.

The traditional form; carries the highest rash risk.

Resin-free tincture or capsule

Reduced rash incidence.

Most widely available commercial format today.

Safety

Resin-containing preparations can cause a widespread itchy maculopapular rash, sometimes severe. Resin-free or isolate preparations reduce this risk. Liver enzyme elevations have been reported anecdotally.

Who should be cautious

Avoid in pregnancy due to unknown safety. Avoid concentrated whole-root tinctures in people prone to rashes or with sensitive skin.

Interactions

No significant interactions reported, though limited data exist.

Frequently asked questions

What is the Lomatium rash?⌄

A red, itchy, measles-like rash that can develop after taking resinous preparations. It resolves after stopping the herb but can take days to weeks.

References

  • Lomatium dissectum on Wikidata — Wikidata link
  • Lomatium dissectum on NIH DSLD (US supplement label database) — NIH Dietary Supplement Label Database link
  • Research on Lomatium dissectum (PubMed search) — PubMed link

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Evidence-based·How we grade evidence

Disclaimer: These statements have not been evaluated by the FDA. This page is educational, not a substitute for personalized medical advice. Evidence grades are AI-assisted assessments — talk to your doctor before starting any new supplement, especially if you’re pregnant, breastfeeding, on medications, or managing a chronic condition.