Drug & supplement interaction

Boxwood + Metoprolol

Metoprolol brand names: Lopressor, Toprol XL.

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 Boxwood and Metoprolol 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 Metoprolol states a food rule worth keeping to, and the two are separately associated with some of the same side effects, which would make a new symptom harder to attribute to one or the other.

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Interaction report

Boxwood and Metoprolol

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 Metoprolol and Boxwood 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.

Boxwood safety at a glance

Boxwood overall Use caution The raw plant is toxic; only processed extracts are used and safety data are limited.
Pregnancy Likely Unsafe When the whole leaf is used orally; avoid using. There is insufficient reliable information available about the safety of boxwood leaf extract when used during... Read the full pregnancy detail
Breastfeeding Likely Unsafe When the whole leaf is used orally; avoid using. There is insufficient reliable information available about the safety of boxwood leaf extract when used during... 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 Metoprolol and Boxwood? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
How we checked

Why No Interaction Is Listed for Metoprolol

Interactions in our licensed database are recorded against drug classes, not just single drug names. Metoprolol is filed under 6 classifications — including beta-blockers, antihypertensive drugs, cytochrome p450 2d6 (cyp2d6) substrates. Boxwood has documented interactions with 2 drug classes — the most serious being anticholinergic drugs (moderate) and cholinergic drugs (moderate) — and none of Metoprolol’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

Boxwood Does Interact With Other Medications

Boxwood has 219 moderate known drug interactions in our database — Metoprolol isn’t one of them. If you take anything else, check it against the full list below.

Moderate 219 No known interaction 2,611 (incl. Metoprolol)
Taking anything else?

Check Another of Your Medications Against Boxwood

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

What to actually watch for

No Interaction Found — But Data Suggests Boxwood and Metoprolol May Share Several of the Same Side Effects

This is not an interaction. Neither one changes how your body handles the other, and nothing here says they react together. What our sources do show is that each has separately been linked to the effects below — so taking both can make those effects more likely to turn up, and harder to pin on one or the other if they do.

  • Diarrhea / Vomiting Additional detail

    Boxwood

    “Orally, boxwood leaf extract seems to be well tolerated. However, ingestion of whole boxwood leaf can cause serious side effects including vomiting, diarrhea, severe colonic spasms, paralysis, and death secondary to asphyxiation (18).

    Topically, the fresh plant and wood can cause allergic contact dermatitis (18, 37073).

    When inhaled, the wood dust can cause rhinoconjunctivitis and bronchitis.”

    Boxwood · Natural Medicines adverse-effect record, reported in acute bronchitis.

    3 sources cited
    1. 5643. Durant J, Chantre P, Gonzalez G, et al. Efficacy and safety of Buxus sempervirens L. preparations (SPV30) in HIV-infected asymptomatic patients: a multicentre, randomized, double-blind, placebo-controlled trial. Phytomedicine 1998;5:1-10. DOI
    2. 18. Gruenwald J, Brendler T, Jaenicke C. PDR for Herbal Medicines. 1st ed. Montvale, NJ: Medical Economics Company, Inc., 1998.
    3. 99904. Carballada F, Prat M, Núñez R, et al. Allergy to boxwood. J Investig Allergol Clin Immunol. 2014;24(5):359-61.

    “Orally, ingestion of whole boxwood leaf can cause serious side effects including vomiting, diarrhea, and severe colonic spasms (18). The extract, however, does not seem to have these effects.”

    Boxwood · Natural Medicines adverse-effect record, reported in diarrhea.

    2 sources cited
    1. 18. Gruenwald J, Brendler T, Jaenicke C. PDR for Herbal Medicines. 1st ed. Montvale, NJ: Medical Economics Company, Inc., 1998.
    2. 5643. Durant J, Chantre P, Gonzalez G, et al. Efficacy and safety of Buxus sempervirens L. preparations (SPV30) in HIV-infected asymptomatic patients: a multicentre, randomized, double-blind, placebo-controlled trial. Phytomedicine 1998;5:1-10. DOI

    Metoprolol

    Listed in the ADVERSE REACTIONS section of the FDA label for Metoprolol. Read the label on DailyMed ›

  • A skin rash Additional detail

    Boxwood

    “Occupational exposure to boxwood dust might cause allergic symptoms. In a case report, a 52-year-old male experienced symptoms such as rhinoconjunctivitis and bronchitis following occupational exposure to boxwood wood dust. Cases of allergic contact dermatitis to fresh boxwood leaves and a boxwood recorder have also been reported (18,37073).”

    Boxwood · Natural Medicines adverse-effect record, reported in acute bronchitis.

    3 sources cited
    1. 99904. Carballada F, Prat M, Núñez R, et al. Allergy to boxwood. J Investig Allergol Clin Immunol. 2014;24(5):359-61.
    2. 18. Gruenwald J, Brendler T, Jaenicke C. PDR for Herbal Medicines. 1st ed. Montvale, NJ: Medical Economics Company, Inc., 1998.
    3. 37073. van Neer, F. J. and van Ginkel, C. J. Allergic contact dermatitis from a boxwood recorder. Contact Dermatitis 1997;36(6):305.

    Metoprolol

    Listed in the ADVERSE REACTIONS section of the FDA label for Metoprolol. Read the label on DailyMed ›

Effects for Metoprolol come from the ADVERSE REACTIONS section of its FDA label; effects for Boxwood come from the Natural Medicines adverse-effect record, quoted above. Wording is matched across sources by our own clinical vocabulary, so treat this as a prompt to pay attention, not a diagnosis.

Special populations

Boxwood in Pregnancy & Breastfeeding

Pregnancy And Lactation Likely Unsafe

When the whole leaf is used orally; avoid using. There is insufficient reliable information available about the safety of boxwood leaf extract when used during pregnancy and lactation; 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 Metoprolol Products Have a Food Rule — Boxwood Should Not Break It

At least one FDA label for a product containing Metoprolol says to take it with food. If you take Boxwood on an empty stomach out of habit, keep them separate — and take Metoprolol with a meal where the label says to.

This may not be true of your version. Food instructions belong to the product, not the ingredient: two Metoprolol 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.

Administer once daily with food or after a meal.

From the Dosage and Administration section of the FDA label we read for Metoprolol — where that label names a specific product, the instruction is that product's. Read the label on DailyMed ›

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.

From our Q&A

Questions About Boxwood or Metoprolol

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

This page covers Boxwood only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Metoprolol page lists 183 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), American Hellebore (major), American Mistletoe (major), Indian Snakeroot (major) and Tyramine (major).

By severity: 5 major · 152 moderate · 26 minor.

From our pharmacist’s overview on the Metoprolol page

“With metoprolol (Lopressor, Toprol XL), a beta-blocker for high blood pressure and heart problems, these interactions deserve genuine care, starting with the five rated major. Most entries pull blood pressure one way or the other: many supplements add to metoprolol's lowering effect and can drop pressure too far, while a few, tyramine…”

Reviewed by 2 · Jul 18, 2026

Open the Metoprolol interaction page

One more smart check

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

We hold 7 real supplement products containing Boxwood, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Boxwood. Even though Boxwood itself has no known interaction with Metoprolol, 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 Boxwood and Metoprolol 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 Boxwood
Steady interest

#1,441 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Metoprolol
Top 10

#7 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 Boxwood reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 13, 2026. The Boxwood and Metoprolol records this page draws on were last updated July 10, 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 Boxwood

What is Boxwood?

Boxwood
  • HIV/immune support
  • Malaria
  • Arthritis
  • Diabetes
  • Skin conditions
  • Fever

Boxwood is an evergreen shrub whose leaves have been used in folk medicine, most notably in some early studies looking at HIV. The whole plant is toxic, so only processed extracts are used, and solid evidence for any health benefit is very limited. Because of real safety concerns, talk with a pharmacist or doctor before trying boxwood.

Buxus sempervirens · Buxaceae · Leaves (processed into extracts) · Capsules, liquid extracts, tinctures

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

Boxwood: dosing

There is no well-established or standardized dose of boxwood for any condition. The strength and quality of commercial extracts can vary a lot from product to product.If you choose to use a boxwood product, follow the directions on the label and do not exceed them. Never use leaves or material from garden boxwood, since the raw plant is toxic.

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

Read the full Boxwood monograph & all interactions
Medication

About Metoprolol

What Is Metoprolol Used For?

Brand names: Lopressor, Toprol XL

Metoprolol is used to treat several heart and blood pressure conditions. Metoprolol succinate extended-release tablets (including Toprol-XL) are approved for high blood pressure, angina pectoris (chest pain from the heart), and heart failure. Metoprolol tartrate tablets (including Lopressor) are approved for high blood pressure, angina, and — when used alongside intravenous metoprolol — to reduce the risk of cardiovascular death after a definite or suspected heart attack.

Metoprolol tartrate injection (intravenous form) is used in hemodynamically stable patients with a definite or suspected acute heart attack to reduce cardiovascular death, and is followed by oral metoprolol therapy. Lowering blood pressure with metoprolol reduces the risk of strokes and heart attacks.

Most-Reported Side Effects for Metoprolol

From FAERS, the FDA’s public side-effect reporting system (0 reports, all brands). Reports are voluntary and are not proof the drug caused the effect.

Fatigue 23,416 reports
Dyspnea 20,183 reports
Diarrhea 19,912 reports
Nausea 19,659 reports
Dizziness 16,726 reports
See full Metoprolol drug information
Keep checking

Other Drugs & Boxwood

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

0Major
219Moderate
0Minor
2,610No known interaction
219 Moderate 2,610 No interaction
Moderate

219 interactions

Showing 60 of 219 moderate interactions — see all 219 on the Boxwood page.

No interaction 2,610 drugs checked — show the list

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

Showing the 60 most looked-up of 2,610 medications checked with no known interaction — see the full Boxwood list.

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

Boxwood References

The 6 references that drive our Boxwood 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. McGuffin M, Hobbs C, Upton R, Goldberg A, eds. American Herbal Products Association's Botanical Safety Handbook. Boca Raton, FL: CRC Press, LLC 1997.
  2. Gruenwald J, Brendler T, Jaenicke C. PDR for Herbal Medicines. 1st ed. Montvale, NJ: Medical Economics Company, Inc., 1998.
  3. Durant J, Chantre P, Gonzalez G, et al. Efficacy and safety of Buxus sempervirens L. preparations (SPV30) in HIV-infected asymptomatic patients: a multicentre, randomized, double-blind, placebo-controlled trial. Phytomedicine 1998;5:1-10. DOI
  4. Orhan, I., Sener, B., Choudhary, M. I., and Khalid, A. Acetylcholinesterase and butyrylcholinesterase inhibitory activity of some Turkish medicinal plants. J Ethnopharmacol 2004;91(1):57-60. PubMed
  5. van Neer, F. J. and van Ginkel, C. J. Allergic contact dermatitis from a boxwood recorder. Contact Dermatitis 1997;36(6):305.
  6. Carballada F, Prat M, Núñez R, et al. Allergy to boxwood. J Investig Allergol Clin Immunol. 2014;24(5):359-61.

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 Boxwood and Metoprolol Together: Common Questions

Is it safe to take Boxwood with Metoprolol?
We do not list a known interaction between Boxwood and Metoprolol. 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.
Do Boxwood and Metoprolol have any of the same side effects?
Yes — our sources link each of them separately to 3 of the same effects. That is not an interaction: neither changes how your body handles the other. It does mean that if one of those effects turns up, it can be harder to tell which one is behind it. They are listed on this page with the source behind each.
Should I take Boxwood and Metoprolol at the same time of day?
At least one FDA label for a product containing Metoprolol says to take it with food. If you take Boxwood on an empty stomach out of habit, keep them separate and take Metoprolol with a meal where the label says to. Food instructions belong to the product rather than the ingredient — two Metoprolol products can differ — so check the directions on your own box. This is about absorption, not an interaction.
How was the Boxwood and Metoprolol combination checked?
Interactions in our licensed database are recorded against drug classes. Metoprolol is filed under 6 classifications, and Boxwood has documented interactions with 2 drug classes — none of Metoprolol'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 Boxwood interact with any other medications?
Yes. Boxwood has 219 documented drug interactions in our database — Metoprolol 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 Metoprolol interact with any supplements?
Yes. Metoprolol has documented interactions with 183 supplements in our database — Boxwood is not one of them. The Metoprolol 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

Boxwood monograph Uses, safety profile, and every drug interaction in one place Metoprolol drug information The full plain-English guide to this medication Metoprolol supplement interactions Every supplement checked against Metoprolol, 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 6 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Metoprolol and Boxwood?

Our pharmacists answer your medication & supplement questions — free.

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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.