Drug & supplement interaction

Boxwood + Crofelemer

Crofelemer brand names: Fulyzaq, Mytesi.

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 Boxwood and Crofelemer 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

Boxwood and Crofelemer

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 Crofelemer 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 Crofelemer and Boxwood? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
How we checked

Why No Interaction Is Listed for Crofelemer

Interactions in our licensed database are recorded against drug classes, not just single drug names. Crofelemer is filed under a single classification — oral drugs. Boxwood has documented interactions with 2 drug classes — the most serious being anticholinergic drugs (moderate) and cholinergic drugs (moderate) — and none of Crofelemer’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 — Crofelemer 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. Crofelemer)
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

What Boxwood Itself Has Been Linked To

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

  • Diarrhea / Vomiting Additional detail

    “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
  • A skin rash Additional detail

    “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.

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

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

Overlapping uses

What Crofelemer Is Prescribed For, and What Boxwood Has Been Studied For

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

Crofelemer is prescribed for: Mytesi (crofelemer) is approved to provide symptomatic relief of non-infectious diarrhea in adult patients with HIV/AIDS who are taking antiretroviral therapy. It is not intended to treat diarrhea caused by an infection. Before starting Mytesi, a doctor will rule out infectious causes of diarrhea.

Boxwood has been studied for:

  • HIV/AIDS studied, not established Boxwood has been studied for this. Natural Medicines rates the evidence: Insufficient Reliable Evidence To Rate Read what the research shows

    Boxwood for hiv/aids

    There is preliminary evidence that a specific boxwood leaf extract (SPV30) 990 mg per day might delay disease progression in HIV-infected patients. It seems to delay decreases in CD4 cell counts, increases in viral load, and/or progression to AIDS in asymptomatic patients with CD4 counts greater than 350 cells per microliter and a relatively low viral load.

    1 source 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

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 Crofelemer on your own; if you are taking Boxwood for the same health topic, tell your prescriber, especially if the medicine is being adjusted to a target.

Everything else you take

See Every Supplement That Interacts With Crofelemer

This page covers Boxwood only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Crofelemer page lists 17 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Coffee Charcoal (moderate), European Mandrake (moderate), Glucomannan (moderate) and Guar Gum (moderate).

By severity: 1 major · 7 moderate · 9 minor.

Open the Crofelemer 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 Crofelemer, 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 Crofelemer 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

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

29 days ago today
Medication Crofelemer
Steady interest

#2,017 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 20, 2026. The Boxwood and Crofelemer 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 Crofelemer

What Is Crofelemer Used For?

Brand names: Fulyzaq, Mytesi

Mytesi (crofelemer) is approved to provide symptomatic relief of non-infectious diarrhea in adult patients with HIV/AIDS who are taking antiretroviral therapy.

It is not intended to treat diarrhea caused by an infection. Before starting Mytesi, a doctor will rule out infectious causes of diarrhea.

Most-Reported Side Effects for Crofelemer

From FAERS, the FDA’s public side-effect reporting system (233 reports, all brands). Reports are voluntary and are not proof the drug caused the effect.

Diarrhea 26 reports
Anxiety 14 reports
Emotional distress 14 reports
Anhedonia 12 reports
Fatigue 11 reports
See full Crofelemer 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 Crofelemer, 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 Crofelemer Together: Common Questions

Is it safe to take Boxwood with Crofelemer?
We do not list a known interaction between Boxwood and Crofelemer. 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 Boxwood and Crofelemer 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 Boxwood in each. That is a conversation for your prescriber, especially if Crofelemer is being adjusted to a target.
How was the Boxwood and Crofelemer combination checked?
Interactions in our licensed database are recorded against drug classes. Crofelemer is filed under 1 classification, and Boxwood has documented interactions with 2 drug classes — none of Crofelemer'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 — Crofelemer 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 Crofelemer interact with any supplements?
Yes. Crofelemer has documented interactions with 17 supplements in our database — Boxwood is not one of them. The Crofelemer 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 Crofelemer drug information The full plain-English guide to this medication Crofelemer supplement interactions Every supplement checked against Crofelemer, 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 Crofelemer 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.