Drug & supplement interaction

Marsh Labrador Tea + Metoprolol

Metoprolol brand names: Lopressor, Toprol XL.

No Known Interaction
Medically reviewed by · Updated July 2026 · Pair last verified Oct 4, 2026
The bottom line No known interaction

We found no known interaction between Marsh Labrador Tea 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

Marsh Labrador Tea 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 Marsh Labrador Tea 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.

Marsh Labrador Tea safety at a glance

Marsh Labrador Tea overall Use caution The plant contains toxic grayanotoxins, so any internal use carries a risk of poisoning.
Pregnancy Likely Unsafe When used orally; avoid using. Marsh Labrador tea is considered to be a potential uterine stimulant and abortifacient. Read the full pregnancy detail
Breastfeeding Avoid Not enough safety data and it contains potentially toxic substances, so avoid use.

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 Marsh Labrador Tea? 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. Marsh Labrador Tea has documented interactions with 1 drug class — the most serious being cns depressants (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

Marsh Labrador Tea Does Interact With Other Medications

Marsh Labrador Tea has 248 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 248 No known interaction 2,582 (incl. Metoprolol)
Taking anything else?

Check Another of Your Medications Against Marsh Labrador Tea

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

What to actually watch for

No Interaction Found — But Data Suggests Marsh Labrador Tea 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.

  • Sweating Additional detail

    Marsh Labrador Tea

    “Orally, large amounts of marsh Labrador tea can cause poisoning due to its ledol constituent (2). The essential oil of marsh Labrador tea can cause severe irritation of the gastrointestinal tract, vomiting, diarrhea, irritation and damage to the kidneys and urinary tract, heavy perspiration, myalgias, and arthralgias.”

    Marsh Labrador Tea · Natural Medicines adverse-effect record, reported in diarrhea.

    2 sources cited
    1. 2. Blumenthal M, ed. The Complete German Commission E Monographs: Therapeutic Guide to Herbal Medicines. Trans. S. Klein. Boston, MA: American Botanical Council, 1998.
    2. 97164. Dampc A, Luczkiewicz M. Bog Labrador tea--the aromatic beverage and spice: a review of origin, processing and safety. J Sci Food Agric. 2015;95(8):1577-83. PubMed

    Metoprolol

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

  • Diarrhea / Vomiting Additional detail

    Marsh Labrador Tea

    “Orally, ledol, a constituent of the essential oil of marsh Labrador tea, can cause gastrointestinal irritation resulting in vomiting, gastroenteritis, and diarrhea.”

    Marsh Labrador Tea · Natural Medicines adverse-effect record, reported in diarrhea.

    1 source cited
    1. 97164. Dampc A, Luczkiewicz M. Bog Labrador tea--the aromatic beverage and spice: a review of origin, processing and safety. J Sci Food Agric. 2015;95(8):1577-83. PubMed

    Metoprolol

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

Reported for Marsh Labrador Tea but not commonly for Metoprolol: seizures.

Effects for Metoprolol come from the ADVERSE REACTIONS section of its FDA label; effects for Marsh Labrador Tea 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

Marsh Labrador Tea in Pregnancy & Breastfeeding

Pregnancy Likely Unsafe

When used orally; avoid using. Marsh Labrador tea is considered to be a potential uterine stimulant and abortifacient.

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 — Marsh Labrador Tea Should Not Break It

At least one FDA label for a product containing Metoprolol says to take it with food. If you take Marsh Labrador Tea 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.

Overlapping uses

What Metoprolol Is Prescribed For, and What Marsh Labrador Tea Has Been Studied For

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

Metoprolol is prescribed for: Metoprolol is used for several heart and blood pressure conditions. Which ones depend on the product you take. High blood pressure (hypertension): metoprolol tartrate tablets, metoprolol succinate extended-release tablets (including Toprol-XL), and Lopressor tablets lower blood pressure. This lowers the risk of strokes and heart attacks.

Read the rest of what Metoprolol is prescribed for

Angina pectoris: these same tablet products are also used for angina. Heart failure: metoprolol succinate extended-release tablets (including Toprol-XL) are used in heart failure. They reduce the risk of cardiovascular death and heart failure hospitalizations. Heart attack: metoprolol tartrate tablets and Lopressor tablets reduce the risk of cardiovascular death after a definite or suspected acute heart attack, in stable patients, when used with intravenous metoprolol. Metoprolol tartrate injection is used in the hospital for the same purpose, followed by oral metoprolol.

Marsh Labrador Tea has been studied for:

  • Kidney failure studied, not established Marsh Labrador Tea has been studied for this. Natural Medicines rates the evidence: Insufficient Reliable Evidence To Rate Read what the research shows

    Marsh Labrador Tea for kidney failure

    Although there has been interest in using oral marsh Labrador tea for kidney failure, there is insufficient reliable information about the clinical effects of marsh Labrador tea for this condition.

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

From our Q&A

Questions About Marsh Labrador Tea 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 Marsh Labrador Tea 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 Marsh Labrador Tea 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

How much people look this up

Where Marsh Labrador Tea 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 Marsh Labrador Tea
Steady interest

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

29 days ago today
Medication Metoprolol
Top 1%

#18 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 Marsh Labrador Tea reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified October 4, 2026. The Marsh Labrador Tea and Metoprolol 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 Marsh Labrador Tea

What is Marsh Labrador Tea?

Marsh Labrador Tea
  • Colds and respiratory complaints
  • Cough and congestion
  • Mild aches and joint discomfort
  • Topical relief of skin irritation, swelling, and insect bites
  • Traditional use as a diuretic

Marsh Labrador tea is a bog-growing shrub used in folk medicine for coughs, colds, and skin problems, but high-quality human evidence for any use is lacking. Because it contains grayanotoxins (andromedotoxin) that can be poisonous, it is not considered safe for routine use, and pregnant or breastfeeding people should avoid it.

Rhododendron tomentosum · Ericaceae · Leaves and flowering twigs (and an essential oil distilled from them) · Tea (infusion), essential oil, topical preparations

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

Marsh Labrador Tea: dosing

There is no established safe or standardized dose for Marsh Labrador tea. Because the plant naturally contains toxic grayanotoxins, even traditional preparations carry risk, and stronger or longer brews increase that risk.If you choose to use a commercial product, follow the directions on the label exactly and do not exceed them. Never assume that "natural" means harmless.

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

Read the full Marsh Labrador Tea monograph & all interactions
Medication

About Metoprolol

What Is Metoprolol Used For?

Brand names: Lopressor, Toprol XL

Metoprolol is used for several heart and blood pressure conditions. Which ones depend on the product you take.

  • High blood pressure (hypertension): metoprolol tartrate tablets, metoprolol succinate extended-release tablets (including Toprol-XL), and Lopressor tablets lower blood pressure. This lowers the risk of strokes and heart attacks.
  • Angina pectoris: these same tablet products are also used for angina.
  • Heart failure: metoprolol succinate extended-release tablets (including Toprol-XL) are used in heart failure. They reduce the risk of cardiovascular death and heart failure hospitalizations.
  • Heart attack: metoprolol tartrate tablets and Lopressor tablets reduce the risk of cardiovascular death after a definite or suspected acute heart attack, in stable patients, when used with intravenous metoprolol. Metoprolol tartrate injection is used in the hospital for the same purpose, followed by oral metoprolol.
See full Metoprolol drug information
Keep checking

Other Drugs & Marsh Labrador Tea

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

0Major
248Moderate
0Minor
2,581No known interaction
248 Moderate 2,581 No interaction
Moderate

248 interactions

Showing 60 of 248 moderate interactions — see all 248 on the Marsh Labrador Tea page.

No interaction 2,581 drugs checked — show the list

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

Showing the 60 most looked-up of 2,581 medications checked with no known interaction — see the full Marsh Labrador Tea list.

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

Marsh Labrador Tea References

The 3 references that drive our Marsh Labrador Tea 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. Blumenthal M, ed. The Complete German Commission E Monographs: Therapeutic Guide to Herbal Medicines. Trans. S. Klein. Boston, MA: American Botanical Council, 1998.
  2. Brinker F. Herb Contraindications and Drug Interactions. 2nd ed. Sandy, OR: Eclectic Medical Publications, 1998.
  3. Dampc A, Luczkiewicz M. Bog Labrador tea--the aromatic beverage and spice: a review of origin, processing and safety. J Sci Food Agric. 2015;95(8):1577-83. 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 Marsh Labrador Tea and Metoprolol Together: Common Questions

Is it safe to take Marsh Labrador Tea with Metoprolol?
We do not list a known interaction between Marsh Labrador Tea 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 Marsh Labrador Tea 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 Marsh Labrador Tea 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 Marsh Labrador Tea 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.
Are Marsh Labrador Tea and Metoprolol 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 Marsh Labrador Tea in each. That is a conversation for your prescriber, especially if Metoprolol is being adjusted to a target.
How was the Marsh Labrador Tea and Metoprolol combination checked?
Interactions in our licensed database are recorded against drug classes. Metoprolol is filed under 6 classifications, and Marsh Labrador Tea has documented interactions with 1 drug class — 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 Marsh Labrador Tea interact with any other medications?
Yes. Marsh Labrador Tea has 248 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 — Marsh Labrador Tea 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

Marsh Labrador Tea 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 3 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Metoprolol and Marsh Labrador Tea?

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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.