Horseradish

BotanicalBest with a meal

What is it

Horseradish (Armoracia rusticana, sometimes Cochlearia armoracia) is a perennial cruciferous plant whose root is used as a pungent condiment and as a traditional medicinal herb for respiratory and urinary complaints.

Evidence for 2 uses

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

Urinary tract / respiratory infections (combination product)

Limited Evidence

A horseradish-nasturtium combination has been studied in European trials for acute bronchitis, sinusitis, and urinary tract infections, with reported benefits. Evidence for horseradish alone is sparse.

Sinus congestion

Mixed Evidence

Traditional use for clearing congestion; the pungent isothiocyanates have an immediate decongestant sensation. No clinical trials of horseradish alone.

How it works

Horseradish root contains glucosinolates that, when the cells are crushed, are converted by the enzyme myrosinase into isothiocyanates - principally allyl isothiocyanate. These pungent compounds produce the characteristic 'heat' and have demonstrated antibacterial activity in laboratory studies. Allyl isothiocyanate is excreted partly through the lungs, which may explain horseradish's traditional use for clearing congestion. It is also cleared via the kidneys. A combination herbal product containing horseradish and nasturtium has been studied in Europe for urinary tract and respiratory infections.

Dosage

There is no standardized dose. Traditional medicinal preparations use 20 grams of fresh root daily for adults. Capsules vary in concentration. DSLD label data did not include a median dose.

When and how to take it

WHEN: As a condiment, with meals. As a herbal preparation, typically 2-3 times daily with food. HOW: Fresh-grated root, prepared condiment, capsule, or as part of a combination product.

2 commercial forms

Compare the main delivery options and what they’re best suited for.

Fresh-grated root

Used as a condiment.

Maximum isothiocyanate release with fresh grating; activity declines quickly.

Dried root capsule/extract

Used in combination herbal products.

Reduced pungency; potency varies.

Safety

Strong amounts can irritate the mouth, throat, stomach, and intestines. Excess use can cause vomiting, diarrhea, and bloody urine. Topical use may cause skin blistering. Generally safe in culinary amounts.

Who should be cautious

Avoid medicinal doses in pregnancy, lactation, and children under 4. People with kidney disease, gastrointestinal ulcers, or thyroid disease should consult a clinician before using medicinal preparations. Culinary use is generally safe.

Interactions

May increase the elimination of levothyroxine and other thyroid hormones; people on thyroid medication should be cautious with high herbal doses. Theoretical additive effects with blood-thinning medications.

Food sources

Prepared horseradish (condiment)

Amount
1 tsp - 2 kcal
%DV
—

Fresh horseradish root

Amount
Highly variable
%DV
—

Frequently asked questions

Can horseradish clear my sinuses?⌄

Fresh horseradish provides immediate temporary relief from the pungent isothiocyanates. It is not a treatment for underlying sinus infection.

Is wasabi the same as horseradish?⌄

Most commercial 'wasabi' is dyed horseradish. True Japanese wasabi (Wasabia japonica) is a different plant in the same family, with similar isothiocyanate chemistry.

References

Horseradish on Wikidata — Wikidata link

Horseradish on NIH DSLD (US supplement label database) — NIH Dietary Supplement Label Database link

Research on Horseradish (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.