Drug & supplement interaction

Phellodendron + Trimethoprim

Trimethoprim brand names: Proloprim, Trimpex.

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 Phellodendron and Trimethoprim 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.

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Interaction report

Phellodendron and Trimethoprim

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 Trimethoprim and Phellodendron 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.

Phellodendron safety at a glance

Phellodendron overall Use caution Generally used short-term in traditional medicine, but human safety data are limited.
Pregnancy Avoid Berberine-containing herbs may not be safe in pregnancy, so avoid use.
Breastfeeding Likely Unsafe When used orally. The berberine constituent of phellodendron 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 Trimethoprim and Phellodendron? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
How we checked

Why No Interaction Is Listed for Trimethoprim

Interactions in our licensed database are recorded against drug classes, not just single drug names. Trimethoprim is filed under 4 classifications — including qt interval-prolonging drugs, antibiotic drugs, oral drugs. Phellodendron has documented interactions with 14 drug classes — the most serious being anticoagulant/antiplatelet drugs (moderate), antidiabetes drugs (moderate) and antihypertensive drugs (moderate) — and none of Trimethoprim’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

Phellodendron Does Interact With Other Medications

Phellodendron has 1,160 moderate known drug interactions in our database — Trimethoprim isn’t one of them. If you take anything else, check it against the full list below.

Moderate 1,160 No known interaction 1,670 (incl. Trimethoprim)
Taking anything else?

Check Another of Your Medications Against Phellodendron

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

What to actually watch for

What Phellodendron Itself Has Been Linked To

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

  • Heartburn Additional detail

    “Orally, a combination product containing extracts of phellodendron plus magnolia has been associated with one report of heartburn in one clinical trial. However, it is unknown if this is related to phellodendron or some other factor.”

    Phellodendron · Natural Medicines adverse-effect record, reported in dyspepsia.

    2 sources cited
    1. 14349. Garrison R, Chambliss WG. Effect of a proprietary Magnolia and Phellodendron extract on weight management: a pilot, double-blind, placebo-controlled clinical trial. Altern Ther Health Med 2006;12:50-4.
    2. 94901. Kalman DS, Feldman S, Feldman R, et al. Effect of a proprietary magnolia and phellodendron extract on stress levels in healthy women: a pilot, double-blind, placebo-controlled clinical trial. Nutr J 2008;7:11.
  • Erection problems Additional detail

    “Orally, a combination product containing extracts of phellodendron plus magnolia has been associated with one report of sexual dysfunction in one clinical trial. However, it is unknown if this is related to phellodendron or some other factor.”

    Phellodendron · Natural Medicines adverse-effect record, reported in antidepressant-induced sexual dysfunction.

    2 sources cited
    1. 14349. Garrison R, Chambliss WG. Effect of a proprietary Magnolia and Phellodendron extract on weight management: a pilot, double-blind, placebo-controlled clinical trial. Altern Ther Health Med 2006;12:50-4.
    2. 94901. Kalman DS, Feldman S, Feldman R, et al. Effect of a proprietary magnolia and phellodendron extract on stress levels in healthy women: a pilot, double-blind, placebo-controlled clinical trial. Nutr J 2008;7:11.
  • Tremor or shakiness / Numbness or tingling / Tiredness / Headache Additional detail

    “Orally, a combination product containing extracts of phellodendron plus magnolia has been associated with single reports of shaking hands, perilabial numbness, fatigue, and headache in clinical research. However, it is unknown if this is related to phellodendron or some other factor.”

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

    2 sources cited
    1. 14349. Garrison R, Chambliss WG. Effect of a proprietary Magnolia and Phellodendron extract on weight management: a pilot, double-blind, placebo-controlled clinical trial. Altern Ther Health Med 2006;12:50-4.
    2. 94901. Kalman DS, Feldman S, Feldman R, et al. Effect of a proprietary magnolia and phellodendron extract on stress levels in healthy women: a pilot, double-blind, placebo-controlled clinical trial. Nutr J 2008;7:11.

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

Special populations

Phellodendron in Pregnancy & Breastfeeding

Lactation Likely Unsafe

When used orally. The berberine constituent of phellodendron 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

From our Q&A

Questions About Phellodendron or Trimethoprim

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

This page covers Phellodendron only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Trimethoprim page lists 59 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), American Hellebore (major), Arsenic (major), Cesium (major) and Ephedra (major).

By severity: 7 major · 41 moderate · 11 minor.

From our pharmacist’s overview on the Trimethoprim page

“Most prescriptions for trimethoprim are short courses for bladder infections, which makes it easy to assume nothing swallowed alongside it matters much. Seven of the 59 supplement and herbal ingredients here rate major, though, and nearly all of them involve heart rhythm: grapefruit in large amounts, ephedra, and a few others can prolo…”

Reviewed by 2 · Jul 18, 2026

Open the Trimethoprim interaction page

One more smart check

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

We hold 393 real supplement products containing Phellodendron, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Phellodendron. Even though Phellodendron itself has no known interaction with Trimethoprim, 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 Phellodendron and Trimethoprim 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 Phellodendron
Top 25%

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

29 days ago today
Medication Trimethoprim
Steady interest

#2,204 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 Phellodendron reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 13, 2026. The Phellodendron and Trimethoprim 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 Phellodendron

What is Phellodendron?

Phellodendron
  • Digestive complaints and diarrhea
  • Inflammation and joint discomfort
  • Stress and weight management (in combination products)
  • Skin conditions (topical, traditional)
  • Antimicrobial support

Phellodendron is a traditional Chinese medicine bark (Huang Bai) that contains berberine and other plant compounds with antimicrobial and anti-inflammatory activity in lab studies. Human evidence for most uses is limited, and it is often sold in combination with other herbs, making its individual effects hard to judge. Talk with your pharmacist or doctor before using it, and avoid it during pregnancy and breastfeeding.

Phellodendron amurense · Rutaceae · Bark (cortex) · Capsules, tablets, powders, tinctures, and dried bark used in teas or decoctions; often combined with other herbs

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

Phellodendron: dosing

There is no well-established, standardized dose of Phellodendron for any health condition. Products vary widely in strength and may contain other herbs, which makes general dosing advice difficult.If you choose to use it, follow the directions on the product label and do not exceed the recommended amount.

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

Read the full Phellodendron monograph & all interactions
Medication

About Trimethoprim

What Is Trimethoprim Used For?

Brand names: Proloprim, Trimpex

Trimethoprim tablets are used to treat initial episodes of uncomplicated urinary tract infections (UTIs). It works against specific bacteria — including E. coli, Proteus mirabilis, Klebsiella pneumoniae, Enterobacter species, and coagulase-negative Staphylococcus species (including S. saprophyticus).

It should only be used when there is a proven or strongly suspected bacterial infection. Your doctor may order a urine culture to confirm which bacteria are present and whether trimethoprim will work against them.

Most-Reported Side Effects for Trimethoprim

From FAERS, the FDA’s public side-effect reporting system (95,001 reports, all brands). Reports are voluntary and are not proof the drug caused the effect.

Fever 6,904 reports
Fatigue 5,992 reports
Diarrhea 5,716 reports
Nausea 5,685 reports
Dyspnea 5,098 reports
See full Trimethoprim drug information
Keep checking

Other Drugs & Phellodendron

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

0Major
1,160Moderate
0Minor
1,669No known interaction
1,160 Moderate 1,669 No interaction
Moderate

1,160 interactions

Showing 60 of 1,160 moderate interactions — see all 1,160 on the Phellodendron page.

No interaction 1,669 drugs checked — show the list

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

Showing the 60 most looked-up of 1,669 medications checked with no known interaction — see the full Phellodendron list.

See the full Phellodendron interactions page
See every supplement checked against Trimethoprim, ranked by severity
Evidence & sources

Phellodendron References

The 22 references that drive our Phellodendron 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. Janbaz KH, Gilani AH. Studies on preventive and curative effects of berberine on chemical-induced hepatotoxicity in rodents. Fitoterapia 2000;71:25-33.. PubMed
  3. 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
  4. Garrison R, Chambliss WG. Effect of a proprietary Magnolia and Phellodendron extract on weight management: a pilot, double-blind, placebo-controlled clinical trial. Altern Ther Health Med 2006;12:50-4.
  5. 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
  6. 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
  7. 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
  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. 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
  11. Sabir M and Bhide NK. Study of some pharmacological actions of berberine. Ind J Physiol & Pharmac 1971;15(3):111-132.
  12. Tripathi YB and Shukla SD. Berberis artistata inhibits PAF induced aggregation of rabbit platelets. Phytotherapy Research 1996;10:628-630.
  13. Yin, J., Xing, H., and Ye, J. Efficacy of berberine in patients with type 2 diabetes mellitus. Metabolism 2008;57(5):712-717. PubMed
  14. 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
  15. 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

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 Phellodendron and Trimethoprim Together: Common Questions

Is it safe to take Phellodendron with Trimethoprim?
We do not list a known interaction between Phellodendron and Trimethoprim. 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.
How was the Phellodendron and Trimethoprim combination checked?
Interactions in our licensed database are recorded against drug classes. Trimethoprim is filed under 4 classifications, and Phellodendron has documented interactions with 14 drug classes — none of Trimethoprim'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 Phellodendron interact with any other medications?
Yes. Phellodendron has 1,160 documented drug interactions in our database — Trimethoprim 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 Trimethoprim interact with any supplements?
Yes. Trimethoprim has documented interactions with 59 supplements in our database — Phellodendron is not one of them. The Trimethoprim 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

Phellodendron monograph Uses, safety profile, and every drug interaction in one place Trimethoprim drug information The full plain-English guide to this medication Trimethoprim supplement interactions Every supplement checked against Trimethoprim, 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 22 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

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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.