Drug & supplement interaction

Blue Flag + Obinutuzumab

Obinutuzumab brand name: Gazyva.

No Known Interaction
Medically reviewed by · Updated July 2026 · Pair last verified Sep 20, 2026
The bottom line No known interaction

We found no known interaction between Blue Flag and Obinutuzumab 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 label for Obinutuzumab states a food rule worth keeping to.

Know someone taking this? Share
Facebook Post Reddit Email
On this page
Interaction report

Blue Flag and Obinutuzumab

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 Obinutuzumab 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 Obinutuzumab and Blue Flag? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
Keep it in perspective

Blue Flag Does Interact With Other Medications

Blue Flag has 1 major, 77 moderate known drug interactions in our database — Obinutuzumab 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. Obinutuzumab)
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

What Blue Flag Itself Has Been Linked To

This is not an interaction — nothing below involves Obinutuzumab. It is the side-effect record for Blue Flag on its own, from the licensed Natural Medicines monograph. If something new turns up after you add Blue Flag, this list is the first place to look.

  • Vomiting / Nausea Additional detail

    “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.
  • Headache Additional detail

    “Orally, the volatile oil constituent of blue flag can cause headache (4).”

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

    1 source cited
    1. 4. Newall CA, Anderson LA, Philpson JD. Herbal Medicine: A Guide for Healthcare Professionals. London, UK: The Pharmaceutical Press, 1996.

Everything above comes from the Natural Medicines adverse-effect record for Blue Flag — expand a row for the licensed statement it rests on. We read the ADVERSE REACTIONS section of Obinutuzumab’s FDA label too, and the two lists don’t meaningfully overlap — which is why no Obinutuzumab column appears here.

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

How to take them

Some Obinutuzumab Products Have a Food Rule — Blue Flag Should Not Break It

At least one FDA label for a product containing Obinutuzumab says to take it on an empty stomach. Most supplements — Blue Flag included — are taken with a meal, so the easy mistake is swallowing both together at breakfast. Where that rule applies, keep Obinutuzumab on its own and move Blue Flag to a meal later in the day.

This may not be true of your version. Food instructions belong to the product, not the ingredient: two Obinutuzumab products can carry different directions, and extended-release forms often differ from immediate-release ones. The label we read is quoted below — check the directions on your own box or bottle, or ask your pharmacist, for how to take the exact product you were given.

650–1,000 mg acetaminophen At least 30 minutes before GAZYVA infusion.

From the Dosage and Administration section of the FDA label we read for Obinutuzumab — where that label names a specific product, the instruction is that product's. See the Obinutuzumab drug page ›

A food rule is not an interaction — it is about how much of the medicine you absorb. The directions that came with your own product, and your pharmacist, outrank anything on this 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 Obinutuzumab, 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 Obinutuzumab 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
Top half

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

29 days ago today
Medication Obinutuzumab
Steady interest

#1,955 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 20, 2026. The Blue Flag and Obinutuzumab 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 Obinutuzumab Injection

What Is Obinutuzumab Injection Used For?

Brand name: Gazyva

Gazyva is used to treat three conditions. For chronic lymphocytic leukemia (CLL), it is given in combination with chlorambucil in patients who have not been treated before. For follicular lymphoma (FL), it is used either with bendamustine (for patients whose disease came back or stopped responding to a rituximab-based regimen) or with chemotherapy (for previously untreated advanced disease) — in both cases followed by Gazyva alone as maintenance therapy.

Gazyva is also approved for active lupus nephritis — a type of kidney inflammation caused by lupus — in adults who are already receiving standard therapy for the condition.

See full Obinutuzumab Injection 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 Obinutuzumab, 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 Obinutuzumab Together: Common Questions

Is it safe to take Blue Flag with Obinutuzumab?
We do not list a known interaction between Blue Flag and Obinutuzumab. 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.
Should I take Blue Flag and Obinutuzumab at the same time of day?
At least one FDA label for a product containing Obinutuzumab says to take it on an empty stomach, and supplements are usually taken with a meal — so taking them together at breakfast is the easy mistake. Where that applies, keep Obinutuzumab on its own and move Blue Flag to a meal later in the day. Food instructions belong to the product rather than the ingredient, so check the directions on your own box. This is about absorption, not an interaction.
Does Blue Flag interact with any other medications?
Yes. Blue Flag has 78 documented drug interactions in our database — Obinutuzumab is simply not one of them. If you take anything else, it is worth checking each one; they are all listed on this page.

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 Obinutuzumab Injection drug information The full plain-English guide to this medication Obinutuzumab supplement interactions Every supplement checked against Obinutuzumab, 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 Obinutuzumab and Blue Flag?

Our pharmacists answer your medication & supplement questions — free.

Ask a pharmacist

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.