Drug & supplement interaction

European Barberry + Phentermine

Phentermine brand names: Adipex-P, Fastin, T Diet, Phentride, Obenix, and others.

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 European Barberry and Phentermine 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.

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

European Barberry and Phentermine

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 Phentermine and European Barberry 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.

European Barberry safety at a glance

European Barberry overall Use caution May be fine short-term for some people, but quality evidence on safe long-term use is limited.
Pregnancy Likely Unsafe When used orally. Berberine is thought to cross the placenta and may cause harm to the fetus. Kernicterus has developed in newborn infants exposed to berberine. Read the full pregnancy detail
Breastfeeding Likely Unsafe When used orally. Berberine and other harmful constituents can be transferred to the infant through breast milk. 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 Phentermine and European Barberry? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
How we checked

Why No Interaction Is Listed for Phentermine

Interactions in our licensed database are recorded against drug classes, not just single drug names. Phentermine is filed under 2 classifications — stimulant drugs, oral drugs. European Barberry has documented interactions with 8 drug classes — the most serious being anticholinergic drugs (moderate), anticoagulant/antiplatelet drugs (moderate) and antidiabetes drugs (moderate) — and none of Phentermine’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

European Barberry Does Interact With Other Medications

European Barberry has 1,210 moderate known drug interactions in our database — Phentermine isn’t one of them. If you take anything else, check it against the full list below.

Moderate 1,210 No known interaction 1,620 (incl. Phentermine)
Taking anything else?

Check Another of Your Medications Against European Barberry

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

What to actually watch for

What European Barberry Itself Has Been Linked To

This is not an interaction — nothing below involves Phentermine. It is the side-effect record for European Barberry on its own, from the licensed Natural Medicines monograph. If something new turns up after you add European Barberry, this list is the first place to look. One entry is worth acting on rather than waiting out — marked below.

  • Yellowing of the skin or eyes / A low platelet count / Anemia / Liver problems / A higher chance of infection Worth acting on Additional detail

    “Orally, a case of hepatitis-associated aplastic anemia is reported in an adult male after consuming European barberry 15 drops and nannari root 15 drops twice a day for 2 weeks. The patient presented with lethargy, loss of appetite, and jaundice that progressed to high-grade fevers, chills, rigors, severe pancytopenia, and abnormal liver function tests. Liver biopsy was suggestive of drug-induced liver injury.”

    European Barberry · Natural Medicines adverse-effect record, reported in anemia.

    1 source cited
    1. 110021. Philips CA, Theruvath AH, Ravindran R. Toxic hepatitis-associated aplastic anaemia after dual homeopathic remedies and Gymnema sylvestre use. BMJ Case Rep 2022;15(3):e247867. PubMed
  • Chills / Reduced appetite / Tiredness Additional detail

    Recorded for European Barberry in the same Natural Medicines adverse-effect record shown under Yellowing of the skin or eyes / A low platelet count / Anemia / Liver problems / A higher chance of infection above.

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

Special populations

European Barberry in Pregnancy & Breastfeeding

Pregnancy Likely Unsafe

When used orally. Berberine is thought to cross the placenta and may cause harm to the fetus. Kernicterus has developed in newborn infants exposed to berberine.

Lactation Likely Unsafe

When used orally. Berberine and other harmful constituents can be transferred to the infant through breast milk.

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

Overlapping uses

What Phentermine Is Prescribed For, and What European Barberry Has Been Studied For

These two come up together because they touch the same health topic — not because they do the same job. Phentermine is a prescription medicine with approved uses on its FDA label. European Barberry is a supplement: what follows is what researchers have looked at it for, and how strong that evidence is.

Phentermine is prescribed for: Phentermine is approved as a short-term addition to a weight-loss program — not a standalone treatment. It is used alongside reduced-calorie eating, increased physical activity, and behavior changes to help manage obesity in adults whose body mass index (BMI) is 30 kg/m² or higher, or 27 kg/m² or higher when other risk factors such as controlled high blood pressure, diabetes, or high cholesterol (hyperlipidemia) are also present. All available phentermine products — including Adipex-P, Lomaira, and various generic capsules and tablets — share this same FDA-approved use. Lomaira tablets are specifically dosed to be taken three times daily before meals, while other formulations are generally taken once daily.

Read the rest of what Phentermine is prescribed for

Treatment is intended to last only a few weeks.

European Barberry has been studied for:

  • Diabetes studied, not established European Barberry has been studied for this. Natural Medicines rates the evidence: Insufficient Reliable Evidence To Rate Read what the research shows

    European Barberry for diabetes

    It is unclear if oral European barberry is beneficial for diabetes.

  • Hyperlipidemia studied, not established European Barberry has been studied for this. Natural Medicines rates the evidence: Insufficient Reliable Evidence To Rate Read what the research shows

    European Barberry for hyperlipidemia

    It is unclear if oral European barberry is beneficial for hyperlipidemia.

Effectiveness ratings and the research summaries above are the verbatim record from the Natural Medicines database, which grades evidence from “Effective” down to “Insufficient Reliable Evidence To Rate”. A rating below the top of that scale means researchers have looked at it — not that it works, and never that it can stand in for a prescribed medicine. Do not stop or replace Phentermine on your own; if you are taking European Barberry for the same health topic, tell your prescriber, especially if the medicine is being adjusted to a target.

From our Q&A

Questions About European Barberry or Phentermine

These are real questions from readers, answered by the pharmacists at HelloPharmacist — written by a person, not generated from a database. Each one covers European Barberry or Phentermine, 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 Phentermine

This page covers European Barberry only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Phentermine page lists 61 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Ephedra (major), Peyote (major), Rauvolfia Vomitoria (major) and Sida Cordifolia (major).

By severity: 5 major · 43 moderate · 13 minor.

From our pharmacist’s overview on the Phentermine page

“Ephedra is the pairing I most want anyone taking phentermine (Adipex-P) to know about. Phentermine is itself a stimulant appetite suppressant that raises heart rate and blood pressure, and ephedra piles the same cardiovascular strain on top of it.”

Reviewed by 2 · Jul 18, 2026

Open the Phentermine interaction page

One more smart check

Taking European Barberry as Part of a Dietary Supplement Product? Check It for Interactions

We hold 2 real supplement products containing European Barberry, each one broken down to its full ingredient list — and combination products often carry several ingredients besides European Barberry. Even though European Barberry itself has no known interaction with Phentermine, 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 European Barberry and Phentermine 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 European Barberry
Steady interest

#1,155 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Phentermine
Top 10%

#225 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 European Barberry reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 20, 2026. The European Barberry and Phentermine 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 European Barberry

What is European Barberry?

European Barberry
  • Digestive upset
  • Antimicrobial support
  • Blood sugar support
  • Cholesterol and metabolic support
  • Skin conditions

European barberry is a shrub whose root, bark, and berries contain berberine, a bitter plant alkaloid that has been studied mostly in isolated form. Some early research on berberine is promising for blood sugar and cholesterol, but high-quality evidence for the whole barberry herb is limited. Talk with your pharmacist or doctor before using it, and avoid it during pregnancy and breastfeeding.

Berberis vulgaris · Berberidaceae · Root, root bark, stem bark, leaf, and fruit (berries) · Capsules, tablets, dried herb, tea, tincture/liquid extract, topical preparations

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

European Barberry: dosing

There is no well-established standard dose for European barberry as a whole herb. Products vary widely in strength and in how much berberine they contain, which makes a single recommended amount difficult to give.If you choose to use a barberry or berberine product, follow the directions on the product label and do not exceed them. They can help you decide if it is appropriate and what amount, if any, is reasonable for you.

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

Read the full European Barberry monograph & all interactions
Medication

About Phentermine

What Is Phentermine Used For?

Brand names: Adipex-P, Fastin, T Diet, Phentride, Obenix, Pbc Phentride, Pbw Phentride, Phentrol #3, Ionamin, Phentrol #6, Phentrol #2, Phentrol #5, Phentrol, Obermine, Phentermine, Suprenza

Phentermine is approved as a short-term addition to a weight-loss program — not a standalone treatment. It is used alongside reduced-calorie eating, increased physical activity, and behavior changes to help manage obesity in adults whose body mass index (BMI) is 30 kg/m² or higher, or 27 kg/m² or higher when other risk factors such as controlled high blood pressure, diabetes, or high cholesterol (hyperlipidemia) are also present.

All available phentermine products — including Adipex-P, Lomaira, and various generic capsules and tablets — share this same FDA-approved use. Lomaira tablets are specifically dosed to be taken three times daily before meals, while other formulations are generally taken once daily. Treatment is intended to last only a few weeks.

See full Phentermine drug information
Keep checking

Other Drugs & European Barberry

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

0Major
1,210Moderate
0Minor
1,619No known interaction
1,210 Moderate 1,619 No interaction
Moderate

1,210 interactions

Showing 60 of 1,210 moderate interactions — see all 1,210 on the European Barberry page.

No interaction 1,619 drugs checked — show the list

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

Showing the 60 most looked-up of 1,619 medications checked with no known interaction — see the full European Barberry list.

See the full European Barberry interactions page
See every supplement checked against Phentermine, ranked by severity
Evidence & sources

European Barberry References

The 15 references that drive our European Barberry 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. Chan E. Displacement of bilirubin from albumin by berberine. Biol Neonate 1993;63:201-8. PubMed
  2. 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
  3. Shamsa F, Ahmadiani A, Khosrokhavar R. Antihistaminic and anticholinergic activity of barberry fruit (Berberis vulgaris) in the guinea-pig ileum. J Ethnopharmacol 1999;64:161-6. PubMed
  4. Fatehi M, Saleh TM, Fatehi-Hassanabad Z, et al. A pharmacological study on Berberis vulgaris fruit extract. J Ethnopharmacol 2005;102:46-52. PubMed
  5. Kostalova, D., Bukovsky, M., Koscova, H., and Kardosova, A. [Anticomplement activity of Mahonia aquifolium bisbenzylisoquinoline alkaloids and berberine extract]. Ceska.Slov.Farm 2001;50(6):286-289.
  6. Fatehi-Hassanabad, Z., Jafarzadeh, M., Tarhini, A., and Fatehi, M. The antihypertensive and vasodilator effects of aqueous extract from Berberis vulgaris fruit on hypertensive rats. Phytother Res 2005;19(3):222-225.
  7. Singh, J. and Kakkar, P. Antihyperglycemic and antioxidant effect of Berberis aristata root extract and its role in regulating carbohydrate metabolism in diabetic rats. J Ethnopharmacol. 5-4-2009;123(1):22-26. PubMed
  8. 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
  9. 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.
  10. Xuan, B., Wang, W., and Li, D. X. Inhibitory effect of tetrahydroberberine on platelet aggregation and thrombosis. Zhongguo Yao Li Xue.Bao. 1994;15(2):133-135.
  11. Gao, C. R., Zhang, J. Q., and Huang, Q. L. [Experimental study on berberin raised insulin sensitivity in insulin resistance rat models]. Zhongguo Zhong.Xi.Yi.Jie.He.Za Zhi. 1997;17(3):162-164. 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. Lazavi F, Mirmiran P, Sohrab G, Nikpayam O, Angoorani P, Hedayati M. The barberry juice effects on metabolic factors and oxidative stress in patients with type 2 diabetes: A randomized clinical trial. Complement Ther Clin Pract. 2018;31:170-174. PubMed
  15. Philips CA, Theruvath AH, Ravindran R. Toxic hepatitis-associated aplastic anaemia after dual homeopathic remedies and Gymnema sylvestre use. BMJ Case Rep 2022;15(3):e247867. PubMed

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 European Barberry and Phentermine Together: Common Questions

Is it safe to take European Barberry with Phentermine?
We do not list a known interaction between European Barberry and Phentermine. 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.
Are European Barberry and Phentermine used for the same thing?
They overlap in purpose, which usually means the real question is whether you need both rather than whether they are safe together. This page lists the shared uses and how strong the evidence is for European Barberry in each. That is a conversation for your prescriber, especially if Phentermine is being adjusted to a target.
How was the European Barberry and Phentermine combination checked?
Interactions in our licensed database are recorded against drug classes. Phentermine is filed under 2 classifications, and European Barberry has documented interactions with 8 drug classes — none of Phentermine'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 European Barberry interact with any other medications?
Yes. European Barberry has 1,210 documented drug interactions in our database — Phentermine 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 Phentermine interact with any supplements?
Yes. Phentermine has documented interactions with 61 supplements in our database — European Barberry is not one of them. The Phentermine 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

European Barberry monograph Uses, safety profile, and every drug interaction in one place Phentermine drug information The full plain-English guide to this medication Phentermine supplement interactions Every supplement checked against Phentermine, 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 15 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Phentermine and European Barberry?

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.