Herb & supplement monograph

Horseradish Drug Interactions, Uses, Effectiveness, Safety & More

Medically reviewed by Dr. Brian Staiger, PharmD, BCPS ·Updated July 2026

What is this page for?

First and foremost: how Horseradish interacts with medications. The heart of this page is the interaction list — every drug Horseradish is known to interact with, and how serious each one is.

But these pages have grown well beyond that into a full monograph — what Horseradish is, what people use it for and how strong the evidence is, its safety and side effects, and answers to the questions we’re asked most — written and reviewed by the clinical staff at HelloPharmacist. It’s educational information from our licensed clinical databases, not medical advice, and we don’t sell or endorse products. Our editorial policy

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Reviewed by licensed pharmacists Sourced from Natural Medicines

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Horseradish Drug Interactions: The Bottom Line

From the HelloPharmacist Editorial Team · Updated July 2026

Based on the available evidence, the overall risk of a clinically significant Horseradish drug interaction appears low for most people. None of the listed interactions are rated major, and the single concern behind them rests on theoretical evidence rather than documented effects in people.

Interactions deserving the most attention

The one area worth attention is thyroid hormone replacement. Horseradish belongs to the cabbage and mustard family, a plant group associated with depressed thyroid function, so in theory it might blunt the effect of thyroid medication. Because thyroid hormone is a closely monitored medicine where even small changes in effect can matter, anyone taking it should be aware of this possibility, even though the concern has not been confirmed in human studies.

What the rest of the list means

Although a fair number of medications appear on the interaction list, they all trace back to this single theoretical thyroid concern. The moderate ratings reflect caution about what might happen, not effects that have actually been shown in people. In practice, that means most combinations with horseradish have not been proven to cause problems.

Check your medications against Horseradish

Based on HelloPharmacist’s Horseradish interaction data and reviewed under our editorial standards.

Interaction report

Drugs that interact with Horseradish

16 medications have a known interaction with Horseradish, graded by severity. Select any drug for the full evidence-based detail.

Don’t want to scroll the list? Just ask.

Tell us the medications you take and we’ll check each one against Horseradish using our pharmacist-reviewed interaction data.

AI summaries are generated from our Horseradish interaction data for education only — always confirm with your pharmacist. How we use AI

2,830 drugs

Read The List Like a Pharmacist

What Severity, Likelihood & Evidence Mean

Severity — How Serious It Can Be

Major. Clinically significant; generally best avoided, or used only under direct professional supervision.
Moderate. May need monitoring, a dose adjustment, or separating the times you take each one.
Minor. Generally not clinically significant, but still worth noting and mentioning to your pharmacist.
No known interaction. Checked against our sources with nothing documented — not the same as proven safety.

Likelihood — How Well It’s Documented

Likely. Well-controlled human studies have demonstrated the likely existence of this interaction
Probable. Interaction has not been documented in well-controlled studies, however, the interaction has been demonstrated in some small human studies or in controlled animal studies in conjunction with multiple case reports.
Possible. Interaction has been documented in animal or in lab research, or the interaction has been documented in humans but is limited to case reports or conflicting clinical research exists
Unlikely. Interaction has been demonstrated in animal or in lab research but has been shown not to occur in humans.

Where This Data Comes From

Interaction records are evidence-graded and sourced from the Natural Medicines database (TRC Healthcare), the same reference used by pharmacists and hospitals.
Each drug listed above links to the full report for that exact Horseradish combination — clinical detail, likelihood, evidence level, and citations.
Content is reviewed by licensed HelloPharmacist pharmacists — see our data sources and editorial standards.

The big picture

The kinds of drugs Horseradish affects

Every type of medication (drug category) Horseradish is known to interact with. Open any category for the detail — or search your exact drug in the checker above.

All 1 drug category Horseradish interacts with

Thyroid Hormone

Theoretically, horseradish might interfere with the effects of thyroid hormone.
Horseradish and other members of the cabbage and mustard family are associated with depressed thyroid function.

Likelihood Possible Evidence D

Monograph

Horseradish: Uses, Safety & Side Effects

Medically reviewed by Dr. Brian Staiger, PharmD, BCPS · Reviewed July 2026 ·

The bottom line

Horseradish is a pungent root used as a food and folk remedy, most often for sinus congestion and urinary tract complaints. Human evidence is limited, and while culinary amounts are generally well tolerated, concentrated supplements can irritate the stomach and should be used cautiously. Talk with your pharmacist or doctor before using horseradish as a medicine.

Scientific name: Armoracia rusticana
Family: Brassicaceae
Part used: Root (fresh or dried)
Common forms: Fresh grated root, dried root powder, prepared condiment (sauce), capsules, tinctures

People commonly use it for

Sinus and respiratory congestion
Urinary tract infections
Digestive support
Antimicrobial
Culinary flavoring

Popular and traditional uses — not proof it works. See “Uses & effectiveness” below for the evidence.

Safety at a glance

OverallUse caution

Food amounts are generally safe, but concentrated supplements may irritate the digestive tract and mucous membranes.

PregnancyBest avoided

Avoid medicinal amounts during pregnancy because safety has not been established.

BreastfeedingLikely Safe

When the root is used orally in amounts commonly found in foods. Horseradish has Generally Recognized as Safe (GRAS) status in the US.

Read the full breastfeeding detail

Pregnancy & breastfeeding ratings are from Natural Medicines (Therapeutic Research Center). Safety guidance is general; always confirm with your pharmacist or doctor for your situation.

Jump to a section

Overview

Horseradish is a hardy perennial plant in the cabbage and mustard family. The part people use is the thick, white root, which has a sharp, hot, pungent taste and smell when grated or cut.

The plant is native to parts of Europe and western Asia and is now grown around the world, including North America. It is best known as a kitchen condiment, often served as a sauce or mixed into other foods.

Beyond cooking, horseradish has a long history in folk medicine. People have traditionally used it for sinus and chest congestion, urinary tract problems, and to support digestion. It is sold today as a fresh root, dried powder, prepared sauce, and in some capsule or tincture products.

How it works

Horseradish contains natural compounds called glucosinolates. When the root is cut or grated, an enzyme converts these into isothiocyanates (including allyl isothiocyanate), which create the sharp smell and burning sensation.

These isothiocyanates are thought to be responsible for most of horseradish's reported effects. In laboratory research they show antimicrobial activity and can irritate mucous membranes, which may explain the watering eyes and runny nose that people notice.

It is important to know that much of this information comes from test-tube and animal studies. How well these effects carry over to the human body, and at what amounts, is not well established.

Effectiveness

Does Horseradish work?

Here’s what the research actually shows for each use — graded by Natural Medicines and reviewed by Dr. Brian Staiger, PharmD.

Evidence overview · 5 uses evaluated

5 Insufficient evidence

How to read these evidence grades

Natural Medicines’ 7-point scale. We show each rating’s label word-for-word.

1EffectiveStrong, consistent evidence it works.

2Likely EffectiveGood evidence, though not yet conclusive.

3Possibly EffectiveSome evidence suggests a benefit.

4Possibly IneffectiveSome evidence it may not help.

5Likely IneffectiveFairly strong evidence it doesn’t help.

6IneffectiveStrong evidence it doesn’t work.

7Insufficient Reliable Evidence to RateToo little research to say either way.

For Horseradish, current evidence isn’t strong enough to rate any specific use. The conditions it has been studied for are listed below.

Also studied for 5 conditions — evidence insufficient to rate

Insufficient Reliable Evidence To Rate Colic