Drug & supplement interaction

Slippery Elm + Diroximel Fumarate

Diroximel Fumarate brand name: Vumerity.

Moderate Interaction
Medically reviewed by · Updated September 2026
The bottom line Moderate

Slippery Elm has a moderate interaction with Diroximel Fumarate. Theoretically, slippery elm may slow the absorption and reduce serum levels of oral drugs.

Read the full interaction report
SeverityModerate
LikelihoodPossible
EvidenceD
What do Severity, Likelihood & Evidence mean?
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Interaction report

Slippery Elm and Diroximel Fumarate

Here is the interaction we found between these two, with the evidence behind it.

Moderate

ORAL DRUGS

Why this applies to Diroximel Fumarate

Diroximel Fumarate falls under ORAL DRUGS — the group Slippery Elm interacts with.

Theoretically, slippery elm may slow the absorption and reduce serum levels of oral drugs.
Slippery elm inner bark contains mucilage, which may interfere with the absorption of orally administered drugs.
Severity Moderate Likelihood Possible Evidence D

Interaction has been documented in animal or in lab research, or the interaction has been documented in humans but is limited to case reports or conflicting clinical research exists.

Dr. Brian Staiger, PharmD, BCPS
Dr. Brian Staiger explains PharmD, Clinical Pharmacist

Here's the simple version: slippery elm forms a slick, gel-like coating in your stomach and gut. The concern is that this gel could act like a barrier and keep some of your Vumerity (diroximel fumarate) from being fully absorbed into your bloodstream. If less gets absorbed, your MS medicine may not work as well at controlling inflammation and protecting your nerves over time.

I want to be honest about how strong this is: it's a theoretical idea based on how the fiber behaves, not proven cases. To stay on the safe side, separating them by a few hours (taking your Vumerity well apart from the slippery elm) is a reasonable plan. Don't change anything on your own, just run the timing past your pharmacist or doctor first.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Brinker F. Herb Contraindications and Drug Interactions. 2nd ed. Sandy, OR: Eclectic Medical Publications, 1998.

What These Ratings Mean

Every interaction above is graded three ways — here’s the key to each label.

Severity how clinically significant the interaction is
Major

Clinically significant. Avoid the combination, or use only under close professional supervision.

Moderate

Usually worth avoiding or managing — may need monitoring, a dose change, or timing apart.

Minor

Generally not serious. Be aware of it and mention it to your pharmacist.

Likelihood how strong the evidence is that the interaction actually happens in people
  • LikelyWell-controlled human studies have demonstrated the likely existence of this interaction.
  • ProbableInteraction has not been documented in well-controlled studies, however, the interaction has been demonstrated in some small human studies or in controlled animal studies in conjunction with multiple case reports.
  • PossibleInteraction has been documented in animal or in lab research, or the interaction has been documented in humans but is limited to case reports or conflicting clinical research exists.
  • UnlikelyInteraction has been demonstrated in animal or in lab research but has been shown not to occur in humans.
Evidence the quality of the studies behind the rating (graded A–D)
  • AHigh-quality meta-analysis (quantitative systematic review).
  • BCase-control study.
  • CConsensus.
  • DAnecdotal evidence.

These ratings are for information only. Never start, stop, or otherwise change your therapy before speaking with your provider.

Keep it in perspective

Slippery Elm Also Interacts With Other Medications

Slippery Elm has 2,021 moderate known drug interactions in our database — the Diroximel Fumarate one above is one of them. If you take anything else, check it against the full list below.

Moderate 2,021 No known interaction 809 (incl. Diroximel Fumarate)
Taking anything else?

Check Another of Your Medications Against Slippery Elm

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

From our Q&A

Questions About Slippery Elm or Diroximel Fumarate

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

This page covers Slippery Elm only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Diroximel Fumarate page lists 106 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Beer (major), Siberian Cocklebur (major), Wine (major) and Active Hexose Correlated Compound (ahcc) (moderate).

By severity: 4 major · 92 moderate · 10 minor.

From our pharmacist’s overview on the Diroximel Fumarate page

“Diroximel fumarate (Vumerity) treats relapsing multiple sclerosis by quieting an overactive immune system, and I read its interaction list with real seriousness. Four of the 106 entries rate major, and none are exotic.”

Reviewed by 2 · Jul 18, 2026

Open the Diroximel Fumarate interaction page

One more smart check

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

We hold 1,490 real supplement products containing Slippery Elm, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Slippery Elm. Your product may carry other ingredients that interact with Diroximel Fumarate too, on top of Slippery Elm — and those would not show on this page. Find your product and we’ll check every ingredient on its label:

How much people look this up

Where Slippery Elm and Diroximel Fumarate 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 Slippery Elm
Top 10%

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

29 days ago today
Medication Diroximel Fumarate
Top half

#1,133 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.

Supplement

About Slippery Elm

What is Slippery Elm?

Slippery Elm
  • Sore throat and cough
  • Heartburn and acid reflux
  • Digestive upset and IBS
  • Skin irritation (topical)
  • Constipation or diarrhea

Slippery elm is a traditional herbal remedy made from the inner bark of a North American elm tree, used mainly to soothe sore throats and irritated digestive tracts. Its mucilage can coat and calm mucous membranes, but solid human evidence for most uses is limited. It is generally considered low-risk for short-term use, but you should still check with your pharmacist or doctor first.

Read the full Slippery Elm monograph & all interactions
Medication

About Diroximel Fumarate

What Is Diroximel Fumarate Used For?

Brand name: Vumerity

Vumerity (diroximel fumarate) is used to treat relapsing forms of multiple sclerosis (MS) in adults. This includes three specific types: clinically isolated syndrome (a first MS episode), relapsing-remitting MS (the most common pattern of flares and recovery), and active secondary progressive MS (a later stage where disability gradually worsens but relapses still occur).

See full Diroximel Fumarate drug information
Keep checking

Other Drugs & Slippery Elm

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

0Major
2,021Moderate
0Minor
808No known interaction
2,021 Moderate 808 No interaction
Moderate

2,021 interactions

Showing 60 of 2,021 moderate interactions — see all 2,021 on the Slippery Elm page.

No interaction 808 drugs checked — show the list

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

Showing the 60 most looked-up of 808 medications checked with no known interaction — see the full Slippery Elm list.

See the full Slippery Elm interactions page
See every supplement checked against Diroximel Fumarate, ranked by severity
Sources

Sources & How We Checked

Interaction details are evidence-graded and sourced from the Natural Medicines database. The medication overview comes from MedlinePlus.

Content is written and reviewed by licensed HelloPharmacist pharmacists. See our data sources and editorial standards for how this information is built and checked.

Parts of this content are provided by the Therapeutic Research Center, LLC.

DISCLAIMER: Currently this does not check for drug-drug interactions. This is not an all-inclusive comprehensive list of potential interactions and is for informational purposes only. Not all interactions are known or well-reported in the scientific literature, and new interactions are continually being reported. Input is needed from a qualified healthcare provider including a pharmacist before starting any therapy. Application of clinical judgment is necessary.

© 2021 Therapeutic Research Center, LLC

Keep exploring
Slippery Elm monograph › Uses, safety, and every drug interaction in one place Diroximel Fumarate supplement interactions › Every supplement checked against Diroximel Fumarate, ranked by severity Diroximel Fumarate drug information › The full plain-English guide to this medication Supplement interaction checker › Check any supplement or product against your medications Browse medications A–Z › Every drug we've checked against herbs & supplements Ask a pharmacist › Free, personal answer from our licensed team
Pharmacist Counseling Corner

Taking Slippery Elm and Diroximel Fumarate Together: Common Questions

Can you take Slippery Elm with Diroximel Fumarate?
There is a moderate interaction, so it may be acceptable with monitoring or timing changes — but check with your pharmacist first. Read the full details on this page and confirm with your pharmacist before combining them.
How serious is the Slippery Elm and Diroximel Fumarate interaction?
We rate it Moderate. This combination may require monitoring, a dose adjustment, or separating the times you take each one. Consult your pharmacist before using them together.

Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy

Still Have a Question About Diroximel Fumarate and Slippery Elm?

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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.