Drug & supplement interaction

Iceland Moss + Leucovorin Calcium

Leucovorin Calcium brand name: Wellcovorin.

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 Iceland Moss and Leucovorin Calcium 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

Iceland Moss and Leucovorin Calcium

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 Leucovorin Calcium and Iceland Moss 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.

Worth understanding: our licensed dataset holds no drug-interaction record for Iceland Moss at all — not against Leucovorin Calcium, and not against any other medication we track. This verdict therefore rests on the absence of any recorded data, not on research that looked at this combination and found nothing. We cannot rule an interaction out.

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.

Iceland Moss safety at a glance

Iceland Moss overall Use caution Generally well tolerated short-term, but human evidence is limited and quality varies between products.
Pregnancy Possibly Unsafe When used orally; avoid Iceland moss due to the potential for lead contamination. Read the full pregnancy detail
Breastfeeding Possibly Unsafe When used orally; avoid Iceland moss due to the potential for lead contamination. 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 Leucovorin Calcium and Iceland Moss? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
What to actually watch for

What Leucovorin Calcium’s Own FDA Label Lists

This is not an interaction — none of it involves Iceland Moss. These are the most notable effects listed in the ADVERSE REACTIONS section of Leucovorin Calcium’s own FDA label, for the medication by itself. Knowing the drug’s own list makes it easier to work out the likely cause if something new turns up while you take both. 5 of them are worth acting on rather than waiting out — marked below.

  • A low white blood cell count Worth acting on mentioned in 5.8% of FDA reports for Leucovorin Calcium
  • A low platelet count Worth acting on
  • Kidney problems Worth acting on
  • Hives Worth acting on
  • A higher chance of infection Worth acting on
  • Mouth irritation or sores
  • Hair loss
  • Reduced appetite
  • Constipation
  • Diarrhea mentioned in 9.5% of FDA reports for Leucovorin Calcium

Showing the 10 most notable of 14 label-listed effects — ranked by how unusual each one is across medicines generally, with serious effects weighted up.

From the ADVERSE REACTIONS section of the FDA label for Leucovorin Calcium. Read the label on DailyMed › Where a percentage is shown, it is the share of 19,003 voluntary FDA FAERS reports for Leucovorin Calcium that mention that effect — a reporting proportion, not an incidence rate and not evidence the drug caused it. Iceland Moss’s licensed record lists no adverse effects our clinical vocabulary could match, so there is no Iceland Moss side to compare — that is a limit of the record, not a statement that Iceland Moss has no side effects.

Special populations

Iceland Moss in Pregnancy & Breastfeeding

Pregnancy And Lactation Possibly Unsafe

When used orally; avoid Iceland moss due to the potential for lead contamination.

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

Everything else you take

See Every Supplement That Interacts With Leucovorin Calcium

This page covers Iceland Moss only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Leucovorin Calcium 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 Leucovorin Calcium interaction page

One more smart check

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

We hold 56 real supplement products containing Iceland Moss, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Iceland Moss. Even though Iceland Moss itself has no known interaction with Leucovorin Calcium, 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 Iceland Moss and Leucovorin Calcium 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 Iceland Moss
Steady interest

#1,296 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Leucovorin Calcium
Top half

#1,325 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 Iceland Moss reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 20, 2026. The Iceland Moss and Leucovorin Calcium 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 Iceland Moss

What is Iceland Moss?

  • Dry cough and throat irritation
  • Sore or inflamed throat and mouth
  • Digestive upset and loss of appetite
  • Bronchial irritation
  • Soothing mucous membranes

Iceland moss is a lichen traditionally used as a soothing remedy for dry cough and throat or mouth irritation, mainly because of its mucilage (gel-forming fibers). High-quality human studies are limited, so its benefits are not well proven. It is generally considered well tolerated for short-term use, but pregnant and breastfeeding people should avoid it due to a lack of safety data.

Cetraria islandica · Parmeliaceae · Whole lichen (thallus) · Tea, lozenges, liquid extracts, tinctures, capsules, syrups

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

Iceland Moss: dosing

There is no official, standardized dose of Iceland moss. Traditional preparations include a tea made from the dried lichen, lozenges, and liquid extracts, and the right amount depends on the specific product.The safest approach is to follow the directions on the product label and not exceed the recommended amount.

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

Read the full Iceland Moss monograph & all interactions
Medication

About Leucovorin

What Is Leucovorin Used For?

Brand name: Wellcovorin

Leucovorin is used to reduce the harmful effects of methotrexate when the body is having trouble clearing it, and to counteract accidental overdoses of folic acid antagonists or dihydrofolate reductase (DHFR) inhibitors — drugs that block the body's ability to use folate. The oral tablet (Leucovorin Calcium) is approved for these uses in adults only. Vykoura injection is also approved to rescue adult and pediatric patients after high-dose methotrexate therapy.

Leucovorin Calcium tablets are approved to treat cerebral folate transport deficiency (FOLR1-CFTD), a rare genetic condition that prevents the brain from getting enough folate, in adults and children. Vykoura injection and leucovorin calcium injection are approved to treat megaloblastic anemia (low red blood cell counts caused by folate deficiency) when oral treatment isn't an option, and to be used alongside fluorouracil (5-FU) to treat metastatic colorectal cancer.

Most-Reported Side Effects for Leucovorin Calcium

From FAERS, the FDA’s public side-effect reporting system (19,003 reports, all brands). Reports are voluntary and are not proof the drug caused the effect.

Diarrhea 1,799 reports
Nausea 1,388 reports
Vomiting 1,135 reports
Neutropenia 1,094 reports
Fever 1,011 reports
See full Leucovorin drug information
Keep checking

Other Drugs & Iceland Moss

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

0Major
0Moderate
0Minor
2,829No known interaction
2,829 No interaction
No interaction 2,829 drugs checked — show the list

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

Showing the 60 most looked-up of 2,829 medications checked with no known interaction — see the full Iceland Moss list.

See the full Iceland Moss interactions page
See every supplement checked against Leucovorin Calcium, ranked by severity
Evidence & sources

Iceland Moss References

The 3 references that drive our Iceland Moss 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. Tyler VE. Herbs of Choice. Binghamton, NY: Pharmaceutical Products Press, 1994.
  2. McGuffin M, Hobbs C, Upton R, Goldberg A, eds. American Herbal Products Association's Botanical Safety Handbook. Boca Raton, FL: CRC Press, LLC 1997.
  3. Gruenwald J, Brendler T, Jaenicke C. PDR for Herbal Medicines. 1st ed. Montvale, NJ: Medical Economics Company, Inc., 1998.

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 Iceland Moss and Leucovorin Calcium Together: Common Questions

Is it safe to take Iceland Moss with Leucovorin Calcium?
We do not list a known interaction between Iceland Moss and Leucovorin Calcium. 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.
Does Leucovorin Calcium interact with any supplements?
Yes. Leucovorin Calcium has documented interactions with 17 supplements in our database — Iceland Moss is not one of them. The Leucovorin Calcium 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

Iceland Moss monograph Uses, safety profile, and every drug interaction in one place Leucovorin drug information The full plain-English guide to this medication Leucovorin Calcium supplement interactions Every supplement checked against Leucovorin Calcium, 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 Leucovorin Calcium and Iceland Moss?

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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.