Major interaction on record — check this product against your medications before combining. Check your meds →
Dietary supplement

Blue Flag Ingredients & Drug Interactions

by Herbal Terra

Blue Flag label
See full label image
Liquid Category: Botanical
Most serious interaction: Major
Clinical methodology reviewed by · Updated Sep 16, 2026 · Label data from the NIH DSLD
What is this page for?

First and foremost: checking Blue Flag against your medications. The heart of this page is the interaction checker and the full interaction report — how this product’s ingredients may interact with prescription and over-the-counter medicines you may be taking.

Around that, we add a pharmacist’s high-level view of the product as a whole — what’s inside, the evidence for its stated use, how transparent the label is, and what safety data exists — so you can see the full picture in one place. It’s educational information from our licensed clinical databases and the clinical staff at HelloPharmacist — not medical advice — and we don’t sell or endorse products. Our editorial policy

The interaction bottom line Most serious interaction: Major

Blue Flag is a dietary supplement by Herbal Terra with 1 active ingredient. Its ingredients are commonly taken for skin conditions like acne and eczema, constipation and digestive complaints, liver and gallbladder support (traditional).Based on those ingredients, 78 medications have a known interaction with it, the most serious rated major. The ingredients most likely to interact are certified organic Blue Flag (Iris versicolor) dried root liquid extract. Use the checker below to test your specific medication, or read the full HelloPharmacist Interaction Report.

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Check Your Meds Against Blue Flag by Herbal Terra

Ask about any prescription or over-the-counter medication and we check it for interactions with Blue Flag by Herbal Terra — and tell you which ingredient is responsible.

Pharmacist-reviewed data Checks every ingredient Answer in seconds
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HelloPharmacist Scorecard of Blue Flag by Herbal Terra

Our pharmacy team’s full take, with four database checks built into the cards below — a summary of what is known, not a grade of the product itself.

From our pharmacy team — supplement deep dive

Generated from HelloPharmacist’s pharmacist-curated databases and editorial rules · Last generated Jul 11, 2026

What’s inside

Full disclosure
Ingredient Transparency · database check
Full

Every active ingredient lists its own amount on the label.

Why this rating?
  • The label discloses an exact amount for 1 of its 1 active ingredient.
  • No proprietary blends here — you can verify the dose of every single component.

This product contains one active ingredient: certified organic blue flag (Iris versicolor) dried root liquid extract. Blue flag root has been used traditionally as a botanical remedy, though we don't hold effectiveness ratings for it in our data.

The extract is delivered in a liquid form with menstruum (the solvent used to prepare the extract) as an inactive ingredient.

Does it work?

Couldn't assess
Evidence for Intended Use · database check
By FDA rules, dietary supplements can’t claim to treat, cure, or prevent disease — so labels speak in careful marketing language. We discern each product’s intended use from its name, label claims, and label statements, then grade the clinical evidence for that use. How these ratings are computed
Not assessable

This is a single-ingredient Blue Flag product and its label doesn't state a use — see Blue Flag's own graded uses on its monograph.

Why this rating?
  • We looked at the product name, claims, and label statements and couldn't find a stated purpose to grade.

We don't hold effectiveness ratings for blue flag in our data, so the strength of evidence for any particular use isn't established here. If you're considering this product for a specific health goal, talk with your pharmacist or doctor about what the current evidence shows.

The evidence, ingredient by ingredient Blue Flag

How safe is it?

Well-documented data
Safety Information · database check
Well characterized

Adverse-effect, pregnancy, and general safety data are on file for most of these ingredients.

Why this rating?
  • We hold adverse-effect (side-effect) data for 1 of the 1 matched ingredient.
  • Pregnancy & breastfeeding safety ratings cover 1 of 1.
  • General safety write-ups exist for 1 of 1.
  • Remember: this measures how much safety information exists. Thin data is not the same as being safe.

Blue flag can cause nausea, vomiting, and throat irritation — especially the fresh root. The volatile oil in blue flag irritates mucous membranes and may trigger headache, eye inflammation, and lacrimation (tearing).

The safety data advises against using blue flag during pregnancy because of potential toxicity and lack of safety information. Breastfeeding is likely unsafe — there isn't enough data to know it's okay, so it's best not to use it while nursing.

Side effects, ingredient by ingredient Blue Flag

Meds to double-check

Major interaction found
Known Interaction Concern · database check
Major identified

At least one ingredient has a documented Major-severity interaction. Check your medications for a personalized result.

Why this rating?
  • 1 of the 1 matched ingredient can interact with medications — Blue Flag.
  • The most serious interaction on file is rated Major.
  • Some involve high-stakes drug classes: anticoagulant / antiplatelet drugs; heart-rhythm medications.
  • For scale: 78 individual medications appear in the full list. A big number alone doesn't make a product dangerous — what matters is whether YOUR medication is on it, so run yours through the interaction checker on this page.

Before taking blue flag, check with your pharmacist if you take digoxin (a heart medication) — overuse increases your risk of adverse effects. Also double-check if you're on warfarin or other blood thinners, or on diuretic drugs, as blue flag can change how these work or worsen side effects like low potassium.

Check your own medication Run your meds through the checker above

The bottom line

Scorecard at a glanceFully disclosed formula with no assessable stated purpose. Major medication interactions have been identified, and safety information is well characterized.

Blue flag is a single-ingredient herbal extract with documented interactions involving your heart, blood thinners, and water pills. If you take digoxin, warfarin, or diuretics, or if you're pregnant or breastfeeding, talk with your pharmacist before starting this product.

Check your exact medications on this page before you begin.

Educational only — not medical advice; always confirm with your pharmacist. Our editorial policy · How we use AI

Assessment coverage: 1 of 1 active ingredient matched to our full ingredient reviews (monographs). Based on the product label dated Sep 25, 2020.

This Scorecard evaluates available label information, ingredient evidence, and known medication-safety considerations. It does not independently verify product identity, purity, potency, contamination, or manufacturing quality. How these ratings are computed

At a glance

General information

Key facts about Blue Flag, straight from the product label.

Brand Herbal Terra
Barcode (UPC) 7429523672694
Net contents 4 Fluid Ounce(s); 120 mL
Market status On market
Date entered into DSLD Sep 25, 2020
DSLD ID 234028
Product type Botanical
Supplement form Liquid
Dietary claims / uses All Other, Structure/Function
Intended target group(s) Adult (18 - 50 Years), Organic, Gluten Free, Sugar Free
From the label
Everything in this section is reproduced from the manufacturer’s own product label — it’s the label speaking, not HelloPharmacist. We show it so you can see exactly what the maker states; we don’t verify or endorse those statements.

Supplement Facts

The label details for Blue Flag by Herbal Terra, sourced from the NIH Dietary Supplement Label Database.

Supplement Facts

Daily Value (DV) Target Group(s):
Adults and children 4 or more years of age
Minimum serving Sizes:
1 mL
Maximum serving Sizes:
1 mL
Servings per container
120
UPC/BARCODE
7429523672694
IngredientAmount% DV
certified organic Blue Flag (Iris versicolor) dried root liquid extract970 mg--

Other ingredients: Menstruum

Tap any ingredient to jump to its full detail below.

Label statements
These statements are the manufacturer’s wording, reproduced from the product label — the label is saying it, not HelloPharmacist. We don’t verify or endorse them.
Formulation

Origin of plant material: USA.

Manufactured in the USA in an FDA registered facility

Sugar free

Dried herb/menstruum ratio: 1:3 Expertly extracted Laboratory tested 330 mg/1 mL Premium product Super concentrated liquid herbal extract

Non GMO

No artificial ingredients, GMO, gluten, color additives, fillers, preservatives or binders. Natural Gluten Free

Suggested/Recommended/Usage/Directions

Direction Shake well before use. Adults take up to 30 drops (1 mL, one full squeeze of the dropper bulb) in 3-4 fl. oz of juice or water up to 4 times a day. We recommend to seek expert medical advice before taking this or any other herbal supplements.

FDA Disclaimer Statement

Notice This product has not been evaluated by the FDA and is not intended to diagnose, treat, cure, or prevent any disease.

Precautions

Caution May have contraindications.

Do not use if you are allergic to any ingredients.

Consult a physician before using during pregnancy, if nursing, or if you are on any medications.

Keep out of the reach of children.

Storage

Store in a cool, dry, dark place.

Formula

Iris versicolor

FDA Statement of Identity

Herbal Supplement

Seals/Symbols

Made in USA Made in an FDA registered facility Natural Gluten Free

Is this label outdated? Report a formula or label change and our pharmacy team will review it.

See for yourself

Blue Flag by Herbal Terra label

The label scan from the NIH Dietary Supplement Label Database. Tap to enlarge.

Blue Flag label

Label images are published by the NIH Dietary Supplement Label Database for the version of this product on file. Always read your actual product label.

View the full label (PDF)
What’s inside

The Ingredients in Blue Flag by Herbal Terra

This is the 1 active ingredient this product is made of. Select it to open its full monograph.

Serving size1 mL Dosage formLiquid Servings per container120 Amounts shown are per serving.

Certified organic Blue Flag (Iris versicolor) dried root liquid extract

Interacts with
78 drugs
970 mg per serving

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...

Certified organic Blue Flag (Iris versicolor) dried root liquid extract monograph & interactions

Other (inactive) ingredients: Menstruum. These complete the product’s ingredient list but are not active constituents.

Interaction report

Blue Flag by Herbal Terra Drug Interactions

Want to check YOUR meds against Blue Flag?

Ask about interactions with your drugs in plain English — “Can I take it with lisinopril?” — and we find you the answer in seconds, ingredient by ingredient.

 Go to the checker
78Drugs
1 Major 77 Moderate

Ingredients driving the most interactions

certified organic Blue Flag (Iris versicolor) dried root liquid extract 78

Individual Drug Interactions

The ingredients in Blue Flag interact with 78 drugs. Click any drug to see the details.

1 of the 1 ingredient in Blue Flag interact with drugs. Each result below shows which ingredient is responsible. certified organic Blue Flag (Iris versicolor) dried root liquid extract

Each ingredient & the kinds of drugs it affects

For each ingredient in Blue Flag with known interactions, here are the types of medications it can affect. Open any type for the detail — or search your exact drug in the checker above.

certified organic Blue Flag (Iris versicolor) dried root liquid extract3 drug types · 78 drugs

Digoxin (Lanoxin)

Theoretically, overuse or abuse of this product increases the risk of adverse effects from cardiac glycoside drugs.

Likelihood Probable Evidence D
Diuretic Drugs

Overuse of blue flag might compound diuretic-induced potassium loss. There is some concern that people taking blue flag along with potassium depleting diuretics might have an increased risk for hypokalemia. Initiation of potassium supplementation or an increase in potassium supplement dose may be necessary for some patients. Some diuretics that can deplete potassium include chlorothiazide (Diuril), chlorthalidone (Thalitone), furosemide (Lasix), hydrochlorothiazide (HCTZ, Hydrodiuril, Microzide), and others.

Likelihood Possible Evidence D
Warfarin (Coumadin)

Blue flag has stimulant laxative effects. In some people blue flag can cause diarrhea. Diarrhea can increase the effects of warfarin, increase international normalized ratio (INR), and increase the risk of bleeding. Advise patients who take warfarin not to take excessive amounts of blue flag.

Likelihood Possible Evidence D
certified organic Blue Flag (Iris versicolor) dried root liquid extract full monograph & interactions
The maker

Brand information

Manufacturer and brand details for Blue Flag, from the product label.

Herbal Terra

See all Herbal Terra products
Name
Herbal Terra
Pharmacist Counseling Corner

Blue Flag by Herbal Terra: Common Questions

Does Blue Flag by Herbal Terra interact with any medications?
Yes. Based on its ingredients, Blue Flag has a known interaction with 78 medications, including 1 rated major. Use the checker to see how it interacts with a specific drug.
How can one product interact with so many drugs?
Blue Flag contains a single active ingredient, and that one ingredient can interact with many different medications on its own. We check it against each medication and show the mechanism responsible.
Where does this information come from?
The product label data comes from the NIH Dietary Supplement Label Database (DSLD); the interaction data is built on the Natural Medicines database and reviewed by HelloPharmacist pharmacists.
Can I take blue flag if I'm pregnant?
No. The safety data advises against it because of potential toxicity and lack of safety information. Talk with your doctor or pharmacist about safer alternatives for whatever you're trying to address.
Is blue flag safe while breastfeeding?
No, breastfeeding is likely unsafe. There isn't enough safety data to know it's okay, so you should not use it while nursing. Ask your pharmacist what options might be safer.
What side effects can blue flag cause?
Blue flag can cause nausea, vomiting, and throat irritation. The volatile oil in it irritates mucous membranes and may trigger headache, eye inflammation, and tearing. The fresh root is more irritating than dried forms.
Can I take blue flag with my water pill?
Be cautious. Blue flag may worsen the potassium loss that diuretics cause, raising your risk of low potassium. Talk with your pharmacist about whether you need potassium monitoring or supplementation if you use both together.
What is blue flag used for?
Blue flag is a traditional herbal extract from Iris versicolor root, but we don't hold effectiveness ratings for it in our data. If you want to know whether it works for a specific condition, ask your pharmacist what the research shows.

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

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Label information is sourced from the NIH Dietary Supplement Label Database and reflects the product version on file; always read your actual product label. This page is for education only and is not a substitute for professional medical advice. Confirm with your pharmacist or doctor before combining supplements and medications.

Blue Flag label
Go deeper

The Full Monographs Behind Blue Flag’s Ingredients

Every ingredient we hold a full HelloPharmacist monograph for — uses, evidence, safety, and the complete interaction list.

Herb & supplement monograph

Blue Flag

Interacts with 78 drugs

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 t...

Read the full Blue Flag monograph →
Sources

Sources & How We Checked

Blue Flag's label data comes from the NIH Dietary Supplement Label Database; the ingredient interaction data is from the Natural Medicines database, reviewed by our pharmacists.

Content is written and reviewed by licensed HelloPharmacist pharmacists. See our data sources and editorial standards for how this information is built and checked.

The 3 references behind this product’s interaction data

Every citation that drives the interaction findings for this product’s ingredients, from the evidence-graded Natural Medicines (TRC Healthcare) database. Open an ingredient to browse its citations — links open the study on PubMed or the publisher’s site.

Blue Flag 3 references
  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.

See these in context on the Blue Flag monograph →

Parts of this content are provided by the Therapeutic Research Center, LLC.

DISCLAIMER: Currently this does not check for drug-drug interactions. This is not an all-inclusive comprehensive list of potential interactions and is for informational purposes only. Not all interactions are known or well-reported in the scientific literature, and new interactions are continually being reported. Input is needed from a qualified healthcare provider including a pharmacist before starting any therapy. Application of clinical judgment is necessary.

© 2021 Therapeutic Research Center, LLC

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