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Dietary supplement

Oregon Grape 400 mg Ingredients & Drug Interactions

by Signature Supplements

Oregon Grape 400 mg label
See full label image
Capsule Category: Botanical
Most serious interaction: Moderate
Clinical methodology reviewed by · Updated Sep 16, 2026 · Label data from the NIH DSLD
What is this page for?

First and foremost: checking Oregon Grape 400 mg 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: Moderate

Oregon Grape 400 mg is a dietary supplement by Signature Supplements with 1 active ingredient. Its ingredients are commonly taken for psoriasis (topical), eczema and other skin conditions, digestive upset.Based on those ingredients, 1,218 medications have a known interaction with it, the most serious rated moderate. The ingredients most likely to interact are Oregon Grape. Use the checker below to test your specific medication, or read the full HelloPharmacist Interaction Report.

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Check Your Meds Against Oregon Grape 400 mg by Signature Supplements

Ask about any prescription or over-the-counter medication and we check it for interactions with Oregon Grape 400 mg by Signature Supplements — and tell you which ingredient is responsible.

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HelloPharmacist Scorecard of Oregon Grape 400 mg by Signature Supplements

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: Oregon grape at 400 mg per capsule. Oregon grape is a plant whose root and stem contain berberine, a compound that research suggests may affect your liver's ability to break down certain medications and may influence blood sugar, bleeding, and blood pressure.

The capsule also includes two inactive ingredients—cellulose and diatomaceous earth—which are fillers and binders that help form the capsule.

Does it work?

Moderate evidence
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

This product doesn't appear to be marketed for a specific use, so we graded Oregon Grape's overall clinical evidence instead.

Moderate

Some clinical evidence supports Oregon Grape for:

Why this rating?
  • We looked at the product name, claims, and label statements and couldn't find a stated purpose to grade.
  • Since the label doesn't commit to one use, we graded the ingredient's overall clinical evidence instead.
  • On file: Psoriasis — rated "Possibly Effective" (Natural Medicines).

Oregon grape is rated possibly effective for psoriasis based on available evidence. For atopic dermatitis (eczema), gastroesophageal reflux disease (GERD), and peptic ulcers, the evidence is insufficient to establish whether it works—we don't have enough reliable data yet to say either way.

The evidence, ingredient by ingredient Oregon Grape

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.

Oral Oregon grape is less well studied than its topical form, so it should be approached carefully. Berberine-containing plants are traditionally avoided in pregnancy, and you should not use this product if you are pregnant.

Because berberine may pass into breast milk and reach infants, avoid use while breastfeeding. When applied to skin, Oregon grape may cause itching, burning, or irritation in some people.

Side effects, ingredient by ingredient Oregon Grape

Meds to double-check

Moderate interaction found
Known Interaction Concern · database check
Moderate identified

The most serious documented interaction for these ingredients is Moderate. Check your medications for a personalized result.

Why this rating?
  • 1 of the 1 matched ingredient can interact with medications — Oregon Grape.
  • The most serious interaction on file is rated Moderate.
  • Some involve high-stakes drug classes: anticoagulant / antiplatelet drugs; immunosuppressants / transplant drugs; diabetes medications.
  • For scale: 1,219 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 Oregon grape, double-check with your pharmacist if you take blood thinners or antiplatelet drugs (warfarin, aspirin, clopidogrel)—this is the most serious concern. Also flag any CNS depressants (opioids, benzodiazepines, sleep aids), blood pressure medications, diabetes drugs, medications broken down by your liver (CYP2D6, CYP2C9, or CYP3A4 substrates—your pharmacist can identify these), or cyclosporine.

Check your own medication Run your meds through the checker above

The bottom line

Scorecard at a glanceFully disclosed formula with some supporting evidence behind its ingredients' uses. Moderate medication interactions have been identified, and safety information is well characterized.

Oregon grape is worth considering if you have psoriasis and want to explore supplement options. If you take blood thinners, blood pressure medications, diabetes drugs, sleep aids, or immunosuppressants, you need to check this product with your pharmacist first.

Pregnant or breastfeeding? Skip it.

Talk with your pharmacist or doctor before starting, especially if you're on any prescription medications.

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, 2025.

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 Oregon Grape 400 mg, straight from the product label.

Brand Signature Supplements
Net contents 100 Capsule(s)
Market status On market
Date entered into DSLD Sep 25, 2025
DSLD ID 338879
Product type Botanical
Supplement form Capsule
Dietary claims / uses All Other, Structure/Function
Intended target group(s) Adult (18 - 50 Years), Women (not pregnant or lactating), Gluten Free, Dairy 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 Oregon Grape 400 mg by Signature Supplements, 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:
2 Capsule(s)
Maximum serving Sizes:
2 Capsule(s)
Servings per container
50
IngredientAmount% DV
Oregon Grape800 mg--

Other ingredients: Cellulose, Diatomaceous Earth

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

Contains no: Chemical Fillers or Binders, Artificial coloring, artificial flavor, preservatives, yeast, corn, milk or milk derivatives, lactose, salt, sodium, soy, sugar, gluten, starch or wheat.

From a GMP Facility

FDA Statement of Identity

Dietary Supplement

Formula

Berberis aquifolium

Suggested/Recommended/Usage/Directions

Directions: For adults, take two (2) capsules daily, more if needed.

Precautions

As a reminder, discuss the supplements and medications you take with your health care providers. Warning: Not intended for use by pregnant or nursing women. If you are taking any medications, consult your doctor before use.

Keep out of reach of children.

Storage

Store in a dry place and avoid excessive heat

FDA Disclaimer Statement

This statement has not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure or prevent any disease.

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

See for yourself

Oregon Grape 400 mg by Signature Supplements label

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

Oregon Grape 400 mg 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 Oregon Grape 400 mg by Signature Supplements

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

Serving size2 Capsule(s) Dosage formCapsule Servings per container50 Amounts shown are per serving.

Oregon Grape

Interacts with
1,218 drugs
800 mg per serving Form: Berberis aquifolium

Oregon grape is a shrub whose root contains berberine and related compounds. The strongest (though still modest) evidence is for topical creams that m...

Oregon Grape monograph & interactions

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

Interaction report

Oregon Grape 400 mg by Signature Supplements Drug Interactions

Want to check YOUR meds against Oregon Grape 400 mg?

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
1,218Drugs
1,218 Moderate

Ingredients driving the most interactions

Oregon Grape 1,218

Individual Drug Interactions

The ingredients in Oregon Grape 400 mg interact with 1,218 drugs. Click any drug to see the details.

1 of the 1 ingredient in Oregon Grape 400 mg interact with drugs. Each result below shows which ingredient is responsible. Oregon Grape

Each ingredient & the kinds of drugs it affects

For each ingredient in Oregon Grape 400 mg 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.

Oregon Grape9 drug types · 1,218 drugs

Anticoagulant/Antiplatelet Drugs

Theoretically, Oregon grape might increase the risk of bleeding when taken with anticoagulant or antiplatelet drugs.
In vitro and in vivo research suggests that berberine, a constituent of Oregon grape, can inhibit platelet aggregation.

Likelihood Possible Evidence D
Antidiabetes Drugs

Theoretically, Oregon grape might increase the risk of hypoglycemia when taken with antidiabetes drugs.
Clinical research suggests that berberine, a constituent of Oregon grape, can lower blood glucose levels.

Likelihood Possible Evidence A
Antihypertensive Drugs

Theoretically, Oregon grape might increase the risk of hypotension when taken with antihypertensive drugs.
Animal research suggests that berberine, a constituent of Oregon grape, can have hypotensive effects. Also, an analysis of clinical evidence suggests that taking berberine in combination with amlodipine (Norvasc) can lower systolic and diastolic blood pressure when compared with taking amlodipine alone.

Likelihood Possible Evidence D
Cns Depressants

Theoretically, Oregon grape might increase the sedative effects of CNS depressants.
Animal research suggests that berberine, a constituent of Oregon grape, can have sedative effects.

Likelihood Possible Evidence D
Cyclosporine (Neoral, Sandimmune)

Theoretically, Oregon grape might increase the effects and adverse effects of cyclosporine.
Berberine, a constituent of Oregon grape, can reduce metabolism of cyclosporine and increase serum levels. It might inhibit cytochrome P450 3A4 (CYP3A4), which metabolizes cyclosporine.

Likelihood Possible Evidence D
Cytochrome P450 2C9 (Cyp2C9) Substrates

Theoretically, Oregon grape might increase serum levels of drugs metabolized by CYP2C9.
Preliminary clinical evidence suggests that berberine, a constituent of Oregon grape, can inhibit cytochrome P450 2C9 (CYP2C9).

Likelihood Possible Evidence B
Cytochrome P450 2D6 (Cyp2D6) Substrates

Theoretically, Oregon grape might increase serum levels of drugs metabolized by CYP2D6.
In vitro research and preliminary clinical evidence suggest that berberine, a constituent of Oregon grape, can inhibit cytochrome P450 2D6 (CYP2D6).

Likelihood Possible Evidence B
Cytochrome P450 3A4 (Cyp3A4) Substrates

Theoretically, Oregon grape might increase serum levels of drugs metabolized by CYP3A4.
In vitro research and preliminary clinical evidence suggest that berberine, a constituent of Oregon grape, moderately inhibits cytochrome P450 3A4 (CYP3A4).

Likelihood Possible Evidence D
P-Glycoprotein Substrates

Theoretically, Oregon grape might increase serum levels of drugs that are P-glycoprotein (P-gp) substrates.
In vitro research suggests that Oregon grape extracts inhibit P-gp efflux.

Likelihood Possible Evidence D
Oregon Grape full monograph & interactions
The maker

Brand information

Manufacturer and brand details for Oregon Grape 400 mg, from the product label.

Signature Supplements

See all Signature Supplements products
Name
Signature Supplements
Street Address
P.O. Box 1112
City
San Clemente
State
CA
Web Address
yoursignaturesupplements.com
Pharmacist Counseling Corner

Oregon Grape 400 mg by Signature Supplements: Common Questions

Does Oregon Grape 400 mg by Signature Supplements interact with any medications?
Yes. Based on its ingredients, Oregon Grape 400 mg has a known interaction with 1,218 medications. Use the checker to see how it interacts with a specific drug.
How can one product interact with so many drugs?
Oregon Grape 400 mg 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 Oregon grape if I'm pregnant or breastfeeding?
No—berberine-containing plants like Oregon grape are traditionally avoided in pregnancy, so don't use it while pregnant. Because berberine may pass into breast milk, avoid it while breastfeeding too. Talk with your doctor or pharmacist if you have questions about your individual situation.
What is Oregon grape actually used for?
It's possibly effective for psoriasis. For other skin conditions like eczema, and for digestive issues like acid reflux or ulcers, we don't have enough reliable evidence yet to say whether it works.
Are there any side effects from taking it by mouth?
Oral Oregon grape is less well studied than when it's applied to skin, so side effects aren't fully documented. When applied topically, some people experience itching, burning, or skin irritation. Start cautiously and tell your pharmacist if you notice anything unusual.
Why does Oregon grape interact with so many medications?
The active compound in Oregon grape, berberine, slows how your liver breaks down certain medications. This can raise the levels of drugs in your blood, which may make them stronger or cause more side effects. It also affects blood clotting, blood pressure, and blood sugar on its own.
Does this product contain anything besides Oregon grape?
It contains two inactive ingredients—cellulose and diatomaceous earth—which are fillers and binders that help form the capsule. The active ingredient is Oregon grape alone.

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

Not sure if Oregon Grape 400 mg is safe with your meds?

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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.

Oregon Grape 400 mg label
Go deeper

The Full Monographs Behind Oregon Grape 400 mg’s Ingredients

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

Herb & supplement monograph

Oregon Grape

Interacts with 1,218 drugs

Oregon grape is a shrub whose root contains berberine and related compounds. The strongest (though still modest) evidence is for topical creams that may slightly ease psoriasis; evidence for...

Read the full Oregon Grape monograph →
Sources

Sources & How We Checked

Oregon Grape 400 mg'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 21 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.

Oregon Grape 21 references
  1. Wiesenauer M, Lydtke R. Mahonia aquifolium in patients with Psoriasis vulgaris; an intraindividual study. Phytomedicine 1996;3:231-5.
  2. Chan E. Displacement of bilirubin from albumin by berberine. Biol Neonate 1993;63:201-8. PubMed
  3. Janbaz KH, Gilani AH. Studies on preventive and curative effects of berberine on chemical-induced hepatotoxicity in rodents. Fitoterapia 2000;71:25-33.. PubMed
  4. Wu X, Li Q, Xin H, Yu A, Zhong M. Effects of berberine on the blood concentration of cyclosporin A in renal transplanted recipients: clinical and pharmacokinetic study. Eur J Clin Pharmacol 2005;61:567-72. PubMed
  5. Gulliver WP, Donsky HJ. A report on three recent clinical trials using Mahonia aquifolium 10% topical cream and a review of the worldwide clinical experience with Mahonia aquifolium for the treatment of plaque psoriasis. Am J Ther 2005;12:398-406. PubMed
  6. Zhang Y, Li X, Zou D, et al. Treatment of type 2 diabetes and dyslipidemia with the natural plant alkaloid berberine. J Clin Endocrinol Metab 2008;93:2559-65. PubMed
  7. Budzinski JW, Foster BC, Vandenhoek S, Arnason JT. An in vitro evaluation of human cytochrome P450 3A4 inhibition by selected commercial herbal extracts and tinctures. Phytomedicine 2000;7:273-82. PubMed
  8. Chatterjee P, Franklin MR. Human cytochrome p450 inhibition and metabolic-intermediate complex formation by goldenseal extract and its methylenedioxyphenyl components. Drug Metab Dispos 2003;31:1391-7. PubMed
  9. Shanbhag, S. M., Kulkarni, H. J., and Gaitonde, B. B. Pharmacological actions of berberine on the central nervous system. Jpn.J Pharmacol 1970;20(4):482-487. PubMed
  10. Wu, J. F. and Liu, T. P. [Effects of berberine on platelet aggregation and plasma levels of TXB2 and 6-keto-PGF1 alpha in rats with reversible middle cerebral artery occlusion]. Yao Xue.Xue.Bao. 1995;30(2):98-102.
  11. Peng, W. H., Hsieh, M. T., and Wu, C. R. Effect of long-term administration of berberine on scopolamine-induced amnesia in rats. Jpn J Pharmacol 1997;74(3):261-266. DOI
  12. Sabir M and Bhide NK. Study of some pharmacological actions of berberine. Ind J Physiol & Pharmac 1971;15(3):111-132.
  13. Tripathi YB and Shukla SD. Berberis artistata inhibits PAF induced aggregation of rabbit platelets. Phytotherapy Research 1996;10:628-630.
  14. Yin, J., Xing, H., and Ye, J. Efficacy of berberine in patients with type 2 diabetes mellitus. Metabolism 2008;57(5):712-717. PubMed
  15. Zhang, H., Wei, J., Xue, R., Wu, J. D., Zhao, W., Wang, Z. Z., Wang, S. K., Zhou, Z. X., Song, D. Q., Wang, Y. M., Pan, H. N., Kong, W. J., and Jiang, J. D. Berberine lowers blood glucose in type 2 diabetes mellitus patients through increasing insulin re
  16. Guo, Y., Chen, Y., Tan, Z. R., Klaassen, C. D., and Zhou, H. H. Repeated administration of berberine inhibits cytochromes P450 in humans. Eur J Clin Pharmacol 2012;68(2):213-217. PubMed
  17. Wei, W., Zhao, H., Wang, A., Sui, M., Liang, K., Deng, H., Ma, Y., Zhang, Y., Zhang, H., and Guan, Y. A clinical study on the short-term effect of berberine in comparison to metformin on the metabolic characteristics of women with polycystic ovary syndro
  18. Hermann, R. and von, Richter O. Clinical evidence of herbal drugs as perpetrators of pharmacokinetic drug interactions. Planta Med 2012;78(13):1458-1477. PubMed
  19. Chun YT, Yip TT, Lau KL, and et al. A biochemical study on the hypotensive effect of berberine in rats. Gen Pharmac 1979;10:177-182. PubMed
  20. Lan J, Zhao Y, Dong F, et al. Meta-analysis of the effect and safety of berberine in the treatment of type 2 diabetes mellitus, hyperlipemia and hypertension. J Ethnopharmacol. 2015;161:69-81. PubMed
  21. Fan Y, Zhou Z, Zhang L. Effect of Oregon grape root extracts on P-glycoprotein mediated transport in in vitro cell lines. J Pharm Pharm Sci 2024;26:11927. PubMed

See these in context on the Oregon Grape 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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