Herb & supplement monograph

Slippery Elm Drug Interactions, Uses, Effectiveness, Safety & More

Medically reviewed by Dr. Brian Staiger, PharmD, BCPS ·Updated July 2026

What is this page for?

First and foremost: how Slippery Elm interacts with medications. The heart of this page is the interaction list — every drug Slippery Elm is known to interact with, and how serious each one is.

But these pages have grown well beyond that into a full monograph — what Slippery Elm is, what people use it for and how strong the evidence is, its safety and side effects, and answers to the questions we’re asked most — written and reviewed by the clinical staff at HelloPharmacist. It’s educational information from our licensed clinical databases, not medical advice, and we don’t sell or endorse products. Our editorial policy

Check Slippery Elm against your medication

Add one medication

✓ Supplement

Slippery Elm

1 Your medication

Start typing any prescription or over-the-counter drug name.

Reviewed by licensed pharmacists Sourced from Natural Medicines

On this page

Slippery Elm Drug Interactions: The Bottom Line

From the HelloPharmacist Editorial Team · Updated July 2026

Based on the available evidence, the overall risk of a clinically significant Slippery Elm drug interaction appears low for most people. Every listed interaction is rated moderate, but all of them trace back to a single theoretical concern that has not been confirmed in human studies.

Interactions deserving the most attention

The one concern in the data applies broadly to oral medications. Slippery elm's inner bark contains mucilage, a gel-like fiber that could coat the gut and slow how quickly medicines taken by mouth are absorbed, possibly lowering the amount that reaches the bloodstream. If this happens at all, it would matter most for medicines where small changes in blood levels count, such as those needing steady, precise dosing. There are no well-documented reports of this actually causing problems in people.

What the rest of the list means

The long list of interacting medications looks alarming, but it reflects one theoretical mechanism applied to nearly every drug taken by mouth, not thousands of separate proven problems. The evidence comes from what mucilage could do in principle, not from human studies showing meaningful changes, so most of these combinations are unlikely to cause real trouble.

Check your medications against Slippery Elm

Based on HelloPharmacist’s Slippery Elm interaction data and reviewed under our editorial standards.

Interaction report

Drugs that interact with Slippery Elm

2022 medications have a known interaction with Slippery Elm, graded by severity. Select any drug for the full evidence-based detail.

Don’t want to scroll the list? Just ask.

Tell us the medications you take and we’ll check each one against Slippery Elm using our pharmacist-reviewed interaction data.

AI summaries are generated from our Slippery Elm interaction data for education only — always confirm with your pharmacist. How we use AI

2,830 drugs

Read The List Like a Pharmacist

What Severity, Likelihood & Evidence Mean

Severity — How Serious It Can Be

Major. Clinically significant; generally best avoided, or used only under direct professional supervision.
Moderate. May need monitoring, a dose adjustment, or separating the times you take each one.
Minor. Generally not clinically significant, but still worth noting and mentioning to your pharmacist.
No known interaction. Checked against our sources with nothing documented — not the same as proven safety.

Likelihood — How Well It’s Documented

Likely. Well-controlled human studies have demonstrated the likely existence of this interaction
Probable. Interaction 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.
Possible. 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
Unlikely. Interaction has been demonstrated in animal or in lab research but has been shown not to occur in humans.

Where This Data Comes From

Interaction records are evidence-graded and sourced from the Natural Medicines database (TRC Healthcare), the same reference used by pharmacists and hospitals.
Each drug listed above links to the full report for that exact Slippery Elm combination — clinical detail, likelihood, evidence level, and citations.
Content is reviewed by licensed HelloPharmacist pharmacists — see our data sources and editorial standards.

The big picture

The kinds of drugs Slippery Elm affects

Every type of medication (drug category) Slippery Elm is known to interact with. Open any category for the detail — or search your exact drug in the checker above.

All 1 drug category Slippery Elm interacts with

Oral Drugs

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.

Likelihood Possible Evidence D

Monograph

Slippery Elm: Uses, Safety & Side Effects

Medically reviewed by Dr. Brian Staiger, PharmD, BCPS · Reviewed July 2026 ·

The bottom line

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.

Scientific name: Ulmus rubra
Family: Ulmaceae
Part used: Inner bark
Common forms: Capsules, tablets, lozenges, powder, tea, throat lozenges, topical pastes

People commonly use it for

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

Popular and traditional uses — not proof it works. See “Uses & effectiveness” below for the evidence.

Safety at a glance

OverallUse caution

Generally well tolerated for short-term use, but high-quality safety data are limited.

PregnancyUse caution

Not enough reliable safety data; some sources caution against using it during pregnancy.

BreastfeedingInsufficient reliable information

Insufficient reliable information available; avoid using. Slippery elm bark has historically been inserted into the cervix to induce abortion. As a re...

Read the full breastfeeding detail

Pregnancy & breastfeeding ratings are from Natural Medicines (Therapeutic Research Center). Safety guidance is general; always confirm with your pharmacist or doctor for your situation.

Jump to a section

Overview

Slippery elm (Ulmus rubra) is a tree native to eastern North America. It is part of the elm family and is known for its rough, reddish-brown bark. The soft, slippery inner bark is the part used in herbal products.

When the inner bark is mixed with water, it forms a thick, gel-like substance called mucilage. People have used slippery elm for centuries in traditional and folk medicine, often to soothe a sore throat, calm an upset stomach, or to help with skin irritation.

Today you can find slippery elm in many forms, including throat lozenges, capsules, powders, and teas. It is a common ingredient in herbal cough and throat products.

How it works

The main active part of slippery elm is its mucilage, a sticky, soluble fiber. When it meets water, it swells into a slick gel.

The leading idea is that this gel coats the lining (mucous membranes) of the throat and digestive tract, forming a soothing, protective layer. This may calm irritation and reduce the feeling of soreness. The mucilage may also trigger the body to make more of its own protective mucus.

As a soluble fiber, slippery elm may also gently affect how the bowels move, which could help with both constipation and loose stools. Much of this understanding comes from the herb's physical properties and laboratory work rather than large human trials, so the exact effects in people are not fully proven.

Effectiveness

Does Slippery Elm work?

Here’s what the research actually shows for each use — graded by Natural Medicines and reviewed by Dr. Brian Staiger, PharmD.

Evidence overview · 8 uses evaluated

8 Insufficient evidence

How to read these evidence grades

Natural Medicines’ 7-point scale. We show each rating’s label word-for-word.

1EffectiveStrong, consistent evidence it works.

2Likely EffectiveGood evidence, though not yet conclusive.

3Possibly EffectiveSome evidence suggests a benefit.

4Possibly IneffectiveSome evidence it may not help.

5Likely IneffectiveFairly strong evidence it doesn’t help.

6IneffectiveStrong evidence it doesn’t work.

7Insufficient Reliable Evidence to RateToo little research to say either way.

For Slippery Elm, current evidence isn’t strong enough to rate any specific use. The conditions it has been studied for are listed below.

Also studied for 8 conditions — evidence insufficient to rate

Insufficient Reliable Evidence To Rate Cancer