Drug & supplement interaction

Blue Flag + Rivaroxaban

Rivaroxaban brand name: Xarelto.

No Known Interaction
Medically reviewed by · Updated July 2026 · Pair last verified Sep 13, 2026
The bottom line No known interaction

We found no known interaction between Blue Flag and Rivaroxaban in our sources. Absence of a documented interaction is not the same as proven safety, and does not guarantee one does not exist. Do not start, stop, or change a medication or supplement based on this page; confirm with your pharmacist or doctor first. Additionally, although there is no interaction, the two are separately associated with some of the same side effects, which would make a new symptom harder to attribute to one or the other.

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Interaction report

Blue Flag and Rivaroxaban

We checked these two against our interaction database. Here is what we found.

No Known Interaction Found

We did not find a documented interaction between Rivaroxaban and Blue Flag in our sources. This does not guarantee that the combination is completely free of risk — there is often limited research on supplements and herbal products, especially around drug interactions.

If you decide to take both, the practical routine is simple: add one new thing at a time and note the date you started it. If the combination is going to disagree with you, it usually shows in the first days to a couple of weeks — and a start date turns “I’ve been feeling off” into something a pharmacist can actually work with. Do not stop a prescribed medicine on your own.

Always talk with your pharmacist or doctor before making changes to your medications or supplements, particularly if you take several medications or have an ongoing health condition.

Blue Flag safety at a glance

Blue Flag overall Use caution The root, especially when fresh, can cause nausea, vomiting, and irritation, so it should be used cautiously.
Pregnancy Avoid Avoid during pregnancy because of potential toxicity and lack of safety data.
Breastfeeding Likely Unsafe When used orally; avoid using. Read the full breastfeeding detail

Pregnancy & breastfeeding ratings are from Natural Medicines (Therapeutic Research Center) — the full detail is in the Special populations card below. Safety guidance is general; always confirm with your pharmacist or doctor for your situation.

Still wondering about combining Rivaroxaban and Blue Flag? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
How we checked

Why No Interaction Is Listed for Rivaroxaban

Interactions in our licensed database are recorded against drug classes, not just single drug names. Rivaroxaban is filed under 5 classifications — including anticoagulant/antiplatelet drugs, p-glycoprotein substrates, cytochrome p450 3a4 (cyp3a4) substrates. Blue Flag has documented interactions with 3 drug classes — the most serious being digoxin (lanoxin) (major), diuretic drugs (moderate) and warfarin (coumadin) (moderate) — and none of Rivaroxaban’s classifications are among them.

Classification data comes from our licensed Natural Medicines dataset. A medication can belong to classes beyond those recorded there, so this describes how the check was run — it is not a safety guarantee.

Keep it in perspective

Blue Flag Does Interact With Other Medications

Blue Flag has 1 major, 77 moderate known drug interactions in our database — Rivaroxaban isn’t one of them. If you take anything else, check it against the full list below.

Major 1 Moderate 77 No known interaction 2,752 (incl. Rivaroxaban)
Taking anything else?

Check Another of Your Medications Against Blue Flag

Covers the 2,830 medications we’ve checked against Blue Flag. Pick one to open its full report.

What to actually watch for

No Interaction Found — But Data Suggests Blue Flag and Rivaroxaban May Share a Side Effect

This is not an interaction. Neither one changes how your body handles the other, and nothing here says they react together. What our sources do show is that each has separately been linked to the effects below — so taking both can make those effects more likely to turn up, and harder to pin on one or the other if they do.

  • Vomiting Additional detail

    Blue Flag

    “Orally, blue flag can cause nausea and vomiting, and the fresh root can irritate mucosa (4,19). Orally and topically, the volatile oil constituent of blue flag irritates mucous membranes and can cause lacrimation, eye inflammation, irritation of the throat, and headache (4).”

    Blue Flag · Natural Medicines adverse-effect record, reported in cluster headache.

    2 sources cited
    1. 4. Newall CA, Anderson LA, Philpson JD. Herbal Medicine: A Guide for Healthcare Professionals. London, UK: The Pharmaceutical Press, 1996.
    2. 19. Brinker F. Herb Contraindications and Drug Interactions. 2nd ed. Sandy, OR: Eclectic Medical Publications, 1998.

    “Orally, blue flag can cause nausea and vomiting and the fresh blue flag root can irritate mucosa (4,19). The volatile oil constituent of blue flag irritates mucous membranes and can cause irritation of the throat (4).”

    Blue Flag · Natural Medicines adverse-effect record, reported in nausea and vomiting.

    2 sources cited
    1. 4. Newall CA, Anderson LA, Philpson JD. Herbal Medicine: A Guide for Healthcare Professionals. London, UK: The Pharmaceutical Press, 1996.
    2. 19. Brinker F. Herb Contraindications and Drug Interactions. 2nd ed. Sandy, OR: Eclectic Medical Publications, 1998.

    Rivaroxaban

    Listed in the ADVERSE REACTIONS section of the FDA label for Rivaroxaban. Read the label on DailyMed ›

Reported for Blue Flag but not commonly for Rivaroxaban: headache and nausea.

Effects for Rivaroxaban come from the ADVERSE REACTIONS section of its FDA label; effects for Blue Flag come from the Natural Medicines adverse-effect record, quoted above. Where a percentage is shown, it is the share of 205,037 voluntary FDA FAERS reports for Rivaroxaban that mention that effect — a reporting proportion, not an incidence rate and not evidence the drug caused it. Wording is matched across sources by our own clinical vocabulary, so treat this as a prompt to pay attention, not a diagnosis.

Special populations

Blue Flag in Pregnancy & Breastfeeding

Lactation Likely Unsafe

When used orally; avoid using.

DISCLAIMER: This tool is intended for informational purposes only, and should not be interpreted as specific medical advice. Patients should consult with a qualified healthcare provider before making decisions about therapies and/or health conditions.© 2026 Therapeutic Research Center

From our Q&A

Questions About Blue Flag or Rivaroxaban

These are real questions from readers, answered by the pharmacists at HelloPharmacist — written by a person, not generated from a database. Each one covers Blue Flag or Rivaroxaban, not necessarily both, but if one is close to what you were about to ask it will usually go further than a database entry can:

Not quite your question? Ask our pharmacists directly — it is free, there is no account required, and answers usually come back within 24 hours.

Everything else you take

See Every Supplement That Interacts With Rivaroxaban

This page covers Blue Flag only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Rivaroxaban page lists 285 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Danshen (major), Grapefruit (major), Piracetam (major) and St. John's Wort (major).

By severity: 5 major · 240 moderate · 40 minor.

From our pharmacist’s overview on the Rivaroxaban page

“Grapefruit is the interaction I would flag first for anyone taking rivaroxaban (Xarelto). It slows how the body clears this blood thinner, and higher levels mean more bleeding risk.”

Reviewed by 2 · Jul 18, 2026

Open the Rivaroxaban interaction page

One more smart check

Taking Blue Flag as Part of a Dietary Supplement Product? Check It for Interactions

We hold 101 real supplement products containing Blue Flag, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Blue Flag. Even though Blue Flag itself has no known interaction with Rivaroxaban, another ingredient on your label might. Find your product and we’ll check every ingredient on its label:

How much people look this up

Where Blue Flag and Rivaroxaban Sit Against Everything Else

Out of every supplement and medication people look up on HelloPharmacist, here is where these two land this week — and which way each has been moving.

Supplement Blue Flag
Steady interest

#1,172 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Rivaroxaban
Top 10

#10 of 2,830 medications looked up here in the last 7 days

29 days ago today

Position among everything looked up on this site, not a measure of how commonly either one is used or how important it is. A supplement can climb this list because of a news story. It counts every request to the page, automated ones included, and nothing here identifies anyone.

Where does our data come from?
  • Source: the Natural Medicines (TRC Healthcare) clinical database — the evidence-graded professional reference for herb & supplement interactions.
  • Citation library: 103,510 references behind our interaction content, 65,311 of them resolved to verified PubMed/DOI sources. See every Blue Flag reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 13, 2026. The Blue Flag and Rivaroxaban records this page draws on were last updated July 11, 2026.
  • What “no known interaction” means: no documented interaction in the sources above — not a guarantee of safety. Supplements are studied far less than prescription drugs, so we say exactly what the evidence supports, and nothing more.
Data structure & sourcing designed and verified by .
Supplement

About Blue Flag

What is Blue Flag?

  • Skin conditions like acne and eczema
  • Constipation and digestive complaints
  • Liver and gallbladder support (traditional)
  • Lymphatic and 'detox' tonic (traditional)
  • Thyroid and glandular swelling (traditional)

Blue Flag is a flowering plant whose root has been used in traditional and herbal medicine for skin and digestive complaints, but there is very little modern scientific evidence to support these uses. The fresh root can be toxic and irritating, so it should be used cautiously, if at all, and avoided in pregnancy and breastfeeding. Talk to a pharmacist or doctor before trying it.

Iris versicolor · Iridaceae · Dried rhizome (root) · Dried root, tincture, liquid extract, capsules, occasionally in topical preparations

An interaction check asks whether these two react with each other — it does not ask whether Blue Flag is a good idea for someone in your situation. Here is what our Blue Flag record says about it on its own.

Blue Flag: dosing

There is no well-established or standardized dose for Blue Flag, and reliable dosing information from quality clinical research is lacking. Traditional sources used small amounts of the dried root or tincture, but these are not validated by modern studies.If a product is used, follow the directions on the label and start low.

From our Blue Flag monograph — the full record covers uses, side effects and every documented interaction.

Read the full Blue Flag monograph & all interactions
Medication

About Rivaroxaban

What Is Rivaroxaban Used For?

Brand name: Xarelto

Rivaroxaban tablets are used to reduce the risk of stroke in adults with nonvalvular atrial fibrillation (an irregular heart rhythm), treat deep vein thrombosis (DVT, a blood clot in a vein) and pulmonary embolism (PE, a blood clot in the lungs), and lower the chances of these clots coming back. They also help prevent clots after hip or knee replacement surgery, protect hospitalized patients at risk for clots, and — in combination with aspirin — reduce the risk of major cardiovascular events in adults with coronary artery disease (CAD) or peripheral artery disease (PAD).

Rivaroxaban tablets are also approved for treating VTE (venous thromboembolism, blood clots in veins) and preventing recurrence in pediatric patients from birth to under 18 years, and for preventing clots in children aged 2 and older with congenital heart disease after the Fontan procedure. Rivaroxaban for oral suspension (available as Rivaroxaban Granule and Xarelto oral suspension) is specifically indicated for these two pediatric uses.

See full Rivaroxaban drug information
Keep checking

Other Drugs & Blue Flag

Browse every other medication we’ve checked against Blue Flag — both the ones with a known interaction and the ones without. Select any drug for the full detail.

1Major
77Moderate
0Minor
2,751No known interaction
1 Major 77 Moderate 2,751 No interaction
Major

1 interaction

Moderate

77 interactions

Showing 60 of 77 moderate interactions — see all 77 on the Blue Flag page.

No interaction 2,751 drugs checked — show the list

We also checked Blue Flag against these medications and found no known interaction in our sources. Open any page to confirm.

Showing the 60 most looked-up of 2,751 medications checked with no known interaction — see the full Blue Flag list.

See the full Blue Flag interactions page
See every supplement checked against Rivaroxaban, ranked by severity
Evidence & sources

Blue Flag References

The 3 references that drive our Blue Flag monograph and interaction data, from the evidence-graded Natural Medicines (TRC Healthcare) database. Citations with a link open the study on PubMed or the publisher’s site.

  1. Newall CA, Anderson LA, Philpson JD. Herbal Medicine: A Guide for Healthcare Professionals. London, UK: The Pharmaceutical Press, 1996.
  2. McGuffin M, Hobbs C, Upton R, Goldberg A, eds. American Herbal Products Association's Botanical Safety Handbook. Boca Raton, FL: CRC Press, LLC 1997.
  3. Brinker F. Herb Contraindications and Drug Interactions. 2nd ed. Sandy, OR: Eclectic Medical Publications, 1998.

Medication overviews come from MedlinePlus (NIH); supplement label data from the NIH Dietary Supplement Label Database. Content is written and reviewed by licensed HelloPharmacist pharmacists — see our data sources and editorial standards.

Pharmacist Counseling Corner

Taking Blue Flag and Rivaroxaban Together: Common Questions

Is it safe to take Blue Flag with Rivaroxaban?
We do not list a known interaction between Blue Flag and Rivaroxaban. That does not guarantee the combination is risk-free, so confirm with your pharmacist or doctor — especially if you take other medications or have a health condition.
Do Blue Flag and Rivaroxaban have any of the same side effects?
Yes — our sources link each of them separately to one of the same effects. That is not an interaction: neither changes how your body handles the other. It does mean that if one of those effects turns up, it can be harder to tell which one is behind it. They are listed on this page with the source behind each.
How was the Blue Flag and Rivaroxaban combination checked?
Interactions in our licensed database are recorded against drug classes. Rivaroxaban is filed under 5 classifications, and Blue Flag has documented interactions with 3 drug classes — none of Rivaroxaban's classifications are among them. A medication can belong to classes beyond those recorded in our dataset, so this describes how the check was run rather than guaranteeing safety.
Does Blue Flag interact with any other medications?
Yes. Blue Flag has 78 documented drug interactions in our database — Rivaroxaban is simply not one of them. If you take anything else, it is worth checking each one; they are all listed on this page.
Does Rivaroxaban interact with any supplements?
Yes. Rivaroxaban has documented interactions with 285 supplements in our database — Blue Flag is not one of them. The Rivaroxaban interaction page linked on this page lists every one, ranked by severity.

Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy

Where next

Keep Exploring

Blue Flag monograph Uses, safety profile, and every drug interaction in one place Rivaroxaban drug information The full plain-English guide to this medication Rivaroxaban supplement interactions Every supplement checked against Rivaroxaban, ranked by severity Supplement interaction checker Check any supplement or product against your medications Browse medications A–Z Every drug we’ve checked against herbs & supplements References The 3 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Rivaroxaban and Blue Flag?

Our pharmacists answer your medication & supplement questions — free.

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This information is for education only and is not a substitute for professional medical advice. Always check with your pharmacist or doctor before starting, stopping, or combining supplements and medications.