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Dietary supplement

Slippery Elm Bark 1,600 mg Ingredients & Drug Interactions

by Nature's Way

Slippery Elm Bark 1,600 mg label
See full label image
Capsule Category: Botanical
Most serious interaction: Moderate
Clinical methodology reviewed by · Updated Sep 16, 2026 · Label data from the NIH DSLD
What is this page for?

First and foremost: checking Slippery Elm Bark 1,600 mg against your medications. The heart of this page is the interaction checker and the full interaction report — how this product’s ingredients may interact with prescription and over-the-counter medicines you may be taking.

Around that, we add a pharmacist’s high-level view of the product as a whole — what’s inside, the evidence for its stated use, how transparent the label is, and what safety data exists — so you can see the full picture in one place. It’s educational information from our licensed clinical databases and the clinical staff at HelloPharmacist — not medical advice — and we don’t sell or endorse products. Our editorial policy

The interaction bottom line Most serious interaction: Moderate

Slippery Elm Bark 1,600 mg is a dietary supplement by Nature's Way with 2 active ingredients. Its ingredients are commonly taken for constipation, diarrhea, high cholesterol.Based on those ingredients, 2,025 medications have a known interaction with it, the most serious rated moderate. The ingredients most likely to interact are Dietary Fiber, Slippery Elm. Use the checker below to test your specific medication, or read the full HelloPharmacist Interaction Report.

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Check Your Meds Against Slippery Elm Bark 1,600 mg by Nature's Way

Ask about any prescription or over-the-counter medication and we check it for interactions with Slippery Elm Bark 1,600 mg by Nature's Way — and tell you which ingredient is responsible.

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HelloPharmacist Scorecard of Slippery Elm Bark 1,600 mg by Nature's Way

Our pharmacy team’s full take, with four database checks built into the cards below — a summary of what is known, not a grade of the product itself.

From our pharmacy team — supplement deep dive

Generated from HelloPharmacist’s pharmacist-curated databases and editorial rules · Last generated Jul 11, 2026

What’s inside

Full disclosure
Ingredient Transparency · database check
Full

Every active ingredient lists its own amount on the label.

Why this rating?
  • The label discloses an exact amount for 2 of its 2 active ingredients.
  • No proprietary blends here — you can verify the dose of every single component.

This product contains one active ingredient: slippery elm (from the inner bark), at 1,600 mg per capsule. The other ingredients — hypromellose, cellulose, and magnesium stearate — are inactive ingredients that help form and preserve the capsule.

Does it work?

Strong evidence
Evidence for Intended Use · database check
By FDA rules, dietary supplements can’t claim to treat, cure, or prevent disease — so labels speak in careful marketing language. We discern each product’s intended use from its name, label claims, and label statements, then grade the clinical evidence for that use. How these ratings are computed
Strong

Clinical evidence supports at least one of this product's ingredients for its stated purpose.

Why this rating?
  • The label markets this product for: Traditional GI tract soothing support.
  • We looked for evidence on: Constipation, Cough, Diarrhea, Inflammatory bowel disease (IBD), Irritable bowel syndrome (IBS), Peptic ulcers — and 4 related terms.
  • The strongest evidence on file: Black Psyllium is rated "Effective" for Constipation (Natural Medicines).
  • Also on file: Black Psyllium is rated "Insufficient Reliable Evidence To Rate" for Diarrhea.
  • Also on file: Slippery Elm is rated "Insufficient Reliable Evidence To Rate" for Constipation, Cough, Inflammatory bowel disease (IBD), Diarrhea, and more.

The evidence for slippery elm doesn't give us a clear picture yet. For cancer, constipation, cough, diarrhea, and inflammatory bowel disease (IBD), the data we hold shows insufficient reliable evidence to rate how well it works.

That doesn't mean it doesn't work — it means we don't have the high-quality research to say one way or the other.

The evidence, ingredient by ingredient Black Psyllium Slippery Elm

How safe is it?

Well-documented data
Safety Information · database check
Well characterized

Adverse-effect, pregnancy, and general safety data are on file for most of these ingredients.

Why this rating?
  • We hold adverse-effect (side-effect) data for 2 of the 2 matched ingredients.
  • Pregnancy & breastfeeding safety ratings cover 2 of 2.
  • General safety write-ups exist for 2 of 2.
  • Remember: this measures how much safety information exists. Thin data is not the same as being safe.

Slippery elm is generally well tolerated in the short term, though high-quality safety data are limited. On the topical side, slippery elm extracts can cause contact dermatitis (a skin rash), and the pollen is a known allergen; some people have reported rash and hives after exposure.

For pregnancy, there isn't enough reliable safety data to know either way — talk with your doctor or pharmacist for personalized advice. The same goes for breastfeeding: not enough information exists to say whether it's safe, so caution is advised and a conversation with your healthcare provider is important.

Side effects, ingredient by ingredient Black Psyllium Slippery Elm

Meds to double-check

Moderate interaction found
Known Interaction Concern · database check
Moderate identified

The most serious documented interaction for these ingredients is Moderate. Check your medications for a personalized result.

Why this rating?
  • 2 of the 2 matched ingredients can interact with medications — Black Psyllium, Slippery Elm.
  • The most serious interaction on file is rated Moderate.
  • Some involve high-stakes drug classes: heart-rhythm medications; lithium.
  • For scale: 2,026 individual medications appear in the full list. A big number alone doesn't make a product dangerous — what matters is whether YOUR medication is on it, so run yours through the interaction checker on this page.

Before you take this product, check any oral medications you're on — slippery elm may reduce how much of them your body absorbs and lower their blood levels, a moderate-level interaction. Use the search tool on this page to confirm your prescriptions are in the clear.

Check your own medication Run your meds through the checker above

The bottom line

Scorecard at a glanceFully disclosed formula with clinical evidence supporting its stated purpose. Moderate medication interactions have been identified, and safety information is well characterized.

Slippery elm might be worth considering if you're interested in digestive or throat support, but the evidence for specific uses isn't yet established in our data. The main concern is that it may slow how your body absorbs many oral medications — so you'll need to space them apart.

Check your exact medications before you start, and talk to your pharmacist to make sure it's a good fit for you.

Educational only — not medical advice; always confirm with your pharmacist. Our editorial policy · How we use AI

Assessment coverage: 2 of 2 active ingredients matched to our full ingredient reviews (monographs). Based on the product label dated Apr 24, 2025.

This Scorecard evaluates available label information, ingredient evidence, and known medication-safety considerations. It does not independently verify product identity, purity, potency, contamination, or manufacturing quality. How these ratings are computed

At a glance

General information

Key facts about Slippery Elm Bark 1,600 mg, straight from the product label.

Brand Nature's Way
Barcode (UPC) 033674171004
Net contents 100 Vegan Capsule(s)
Market status On market
Date entered into DSLD Apr 24, 2025
DSLD ID 328064
Product type Botanical
Supplement form Capsule
Dietary claims / uses All Other, Structure/Function
Intended target group(s) Vegan, Vegetarian, Adult (18 - 50 Years), Gluten Free, Dairy Free
From the label
Everything in this section is reproduced from the manufacturer’s own product label — it’s the label speaking, not HelloPharmacist. We show it so you can see exactly what the maker states; we don’t verify or endorse those statements.

Supplement Facts

The label details for Slippery Elm Bark 1,600 mg by Nature's Way, sourced from the NIH Dietary Supplement Label Database.

Supplement Facts

Daily Value (DV) Target Group(s):
Adults and children 4 or more years of age
Minimum serving Sizes:
4 Capsule(s)
Maximum serving Sizes:
4 Capsule(s)
Servings per container
25
UPC/BARCODE
033674171004
IngredientAmount% DV
Calories5 Calorie(s)--
Total Carbohydrates2 Gram(s)1%
Dietary Fiber1 Gram(s)4%
Slippery Elm1.6 Gram(s)--

Other ingredients: Hypromellose, Cellulose, Magnesium Stearate

Tap any ingredient to jump to its full detail below.

Label statements
These statements are the manufacturer’s wording, reproduced from the product label — the label is saying it, not HelloPharmacist. We don’t verify or endorse them.
Formulation

Traditional GI support Botanicals are sourced where they grow best Native to North America, where it's been used for centuries Made with the quality you trust

Gluten free. No wheat, corn, soy, dairy, gelatin, or artificial colors or flavors. Vegan V Gelatin Free

Vegan V Gelatin Free

Bottled and tested in the USA

Traditionally used to soothe the GI Tract Plant powered

Non GMO Project Verified nongmoproject.org

General Statements

Explore more products at naturesway.com 50% Bottle made from 50% post-consumer recycled plastic Questions? 1-800-962-8873 / naturesway.com

Seals/Symbols

Vegan V Gelatin Free

Non GMO Project Verified nongmoproject.org

Brand IP Statement(s)

Copyright 2024

FDA Disclaimer Statement

These statements have not been evaluated by the Food & Drug Administration. This statement is not intended to diagnose, treat, cure, or prevent any disease.

Formula

Slippery Elm Bark 1,600 MG per 4-capsule serving

FDA Statement of Identity

Dietary Supplement

Suggested/Recommended/Usage/Directions

Recommendation: Adults take 4 capsules three times daily with warm water between meals.

Precautions

Warning: Slippery Elm should not be taken together with any medications as it may interfere with absorption. If you are pregnant, nursing, or taking any medications, consult a healthcare professional before use.

Keep out of reach of children.

Safety sealed with inner seal. Do not use if seal is broken or missing.

Storage

Keep tightly closed. Store at room temperature. Avoid excessive heat and direct sunlight.

Is this label outdated? Report a formula or label change and our pharmacy team will review it.

See for yourself

Slippery Elm Bark 1,600 mg by Nature's Way label

The label scan from the NIH Dietary Supplement Label Database. Tap to enlarge.

Slippery Elm Bark 1,600 mg label

Label images are published by the NIH Dietary Supplement Label Database for the version of this product on file. Always read your actual product label.

View the full label (PDF)
What’s inside

The Ingredients in Slippery Elm Bark 1,600 mg by Nature's Way

These are the 2 active ingredients this product is made of. Select any to open its full monograph.

Serving size4 Capsule(s) Dosage formCapsule Servings per container25 Amounts shown are per serving.

Most supplement products combine several ingredients, and a medication can interact with the product through any one of them. Each ingredient below shows whether it has known drug interactions.

Dietary Fiber

Interacts with
2,025 drugs
1 Gram(s) per serving

Black psyllium is a soluble-fiber supplement made from the seeds of a Plantago plant, used mostly to ease constipation and support digestive health. I...

Dietary Fiber monograph & interactions

Slippery Elm

Interacts with
2,022 drugs
1.6 Gram(s) per serving

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 di...

Slippery Elm monograph & interactions

Other (inactive) ingredients: Hypromellose, Cellulose, Magnesium Stearate. These complete the product’s ingredient list but are not active constituents.

Interaction report

Slippery Elm Bark 1,600 mg by Nature's Way Drug Interactions

Want to check YOUR meds against Slippery Elm Bark 1,600 mg?

Ask about interactions with your drugs in plain English — “Can I take it with lisinopril?” — and we find you the answer in seconds, ingredient by ingredient.

 Go to the checker
2,025Drugs
2,022 Moderate 3 Minor

Ingredients driving the most interactions

Dietary Fiber 2,025
Slippery Elm 2,022

Individual Drug Interactions

The ingredients in Slippery Elm Bark 1,600 mg interact with 2,025 drugs. Click any drug to see the details.

2 of the 2 ingredients in Slippery Elm Bark 1,600 mg interact with drugs. Each result below shows which ingredient is responsible. Dietary Fiber Slippery Elm

Each ingredient & the kinds of drugs it affects

For each ingredient in Slippery Elm Bark 1,600 mg with known interactions, here are the types of medications they can affect. Open any type for the detail — or search your exact drug in the checker above.

Dietary Fiber7 drug types · 2,025 drugs

Carbamazepine (Tegretol)

Theoretically, black psyllium might reduce the effects of carbamazepine and increase the risk for convulsions.
Theoretically, black psyllium might reduce carbamazepine absorption. A preliminary study using blond psyllium reported decreased carbamazepine bioavailability due to binding of the drug to psyllium, as well as reduction of available fluid in the gut for dissolution of the drug. This interaction may also occur with black psyllium.

Likelihood Probable Evidence D
Lithium

Theoretically, taking black psyllium at the same time as lithium might reduce lithium absorption.
The fiber in black psyllium might reduce lithium absorption and plasma levels. Some case reports describe a reduction in plasma lithium levels with concomitant administration of blond psyllium. This was reversed when psyllium was stopped. This interaction may also occur with black psyllium.

Likelihood Probable Evidence D
Metformin (Glucophage)

Theoretically, black psyllium might increase the therapeutic and adverse effects of metformin.
Animal research shows that concurrent consumption of blond psyllium with metformin slows and increases the absorption of metformin. This interaction may also occur with black psyllium. To avoid changes in absorption, take psyllium 30-60 minutes after metformin.

Likelihood Possible Evidence D
Olanzapine (Zyprexa)

Theoretically, taking black psyllium at the same time as olanzapine might reduce olanzapine absorption.
The fiber in black psyllium might decrease the absorption of olanzapine. A single case report describes a reduction in the effectiveness of olanzapine when it was concomitantly administered with an unspecified type of psyllium 3 grams orally twice daily. This effect was reversed when psyllium was stopped.

Likelihood Possible Evidence D
Digoxin (Lanoxin)

Theoretically, taking black psyllium at the same time as digoxin might reduce digoxin absorption and decrease digoxin levels.
Psyllium might bind digoxin in the gut. However, some clinical evidence suggests that psyllium does not impact digoxin absorption.

Likelihood Unlikely Evidence B
Ethinyl Estradiol

Theoretically, taking black psyllium at the same time as ethinyl estradiol might alter levels of estradiol.
Concurrent use of blond psyllium with ethinyl estradiol results in a slight increase in the extent of ethinyl estradiol absorption and a slower rate of absorption. This is unlikely to be clinically significant.

Likelihood Unlikely Evidence D
Oral Drugs

Theoretically, psyllium might increase, decrease, or have no effect on the absorption of oral drugs.
Psyllium seems to have variable effects on drug absorption. To avoid changes in absorption, take psyllium 30-60 minutes after oral medications. Animal research shows that blond psyllium delays and increases the absorption of metformin and ethinyl estradiol. Case reports and animal research suggest that blond psyllium might reduce absorption of lithium, digoxin, olanzapine, and carbamazepine. Finally, some pharmacokinetic studies show that psyllium does not affect the absorption of levothyroxine or warfarin. Although many of these studies evaluated blond psyllium, the fiber content in black psyllium may have similar effects.

Likelihood Possible Evidence B
Dietary Fiber full monograph & interactions

Slippery Elm1 drug type · 2,022 drugs

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
Slippery Elm full monograph & interactions
The maker

Brand information

Manufacturer and brand details for Slippery Elm Bark 1,600 mg, from the product label.

Nature's Way

See all Nature's Way products
Name
Nature's Way Brands, LLC
City
Green Bay
State
WI
ZipCode
54311
Phone Number
1-800-962-8873
Web Address
naturesway.com
Pharmacist Counseling Corner

Slippery Elm Bark 1,600 mg by Nature's Way: Common Questions

Does Slippery Elm Bark 1,600 mg by Nature's Way interact with any medications?
Yes. Based on its ingredients, Slippery Elm Bark 1,600 mg has a known interaction with 2,025 medications. Use the checker to see how it interacts with a specific drug.
How can one product interact with so many drugs?
Slippery Elm Bark 1,600 mg contains 2 active ingredients, and an interaction can come from any of them. We check every ingredient, combine the results into one list per medication, and show which ingredient and mechanism is responsible.
Where does this information come from?
The product label data comes from the NIH Dietary Supplement Label Database (DSLD); the interaction data is built on the Natural Medicines database and reviewed by HelloPharmacist pharmacists.
Will slippery elm interfere with my prescription medications?
It potentially can. The mucilage in slippery elm may slow how your body absorbs oral drugs, which could lower their blood levels. Taking your medications at least 2 hours apart from slippery elm helps reduce this risk. Always check your exact prescriptions with the tool on this page — it affects a wide range of oral drugs.
Is slippery elm safe to use while I'm pregnant?
There isn't enough reliable safety data to know either way. Some sources caution against it during pregnancy. Talk with your doctor or pharmacist about whether it's right for you — they can weigh your individual situation.
Can I take slippery elm while breastfeeding?
There's too little information on safety while breastfeeding, so caution is advised. Your pharmacist or doctor can discuss this with you and help you decide if it's appropriate for your situation.
Does slippery elm actually work for cough or digestive problems?
The research we have doesn't give us a clear answer yet. For cough, constipation, diarrhea, and inflammatory bowel disease, the evidence is too limited to reliably rate how well it works.
Can slippery elm cause a skin rash or allergic reaction?
Yes, it can. Slippery elm extracts applied to skin may cause contact dermatitis (a rash), and the pollen is a known allergen. Some people have reported hives or rash after exposure to slippery elm or its compounds.

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

Not sure if Slippery Elm Bark 1,600 mg is safe with your meds?

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Label information is sourced from the NIH Dietary Supplement Label Database and reflects the product version on file; always read your actual product label. This page is for education only and is not a substitute for professional medical advice. Confirm with your pharmacist or doctor before combining supplements and medications.

Slippery Elm Bark 1,600 mg label
Go deeper

The Full Monographs Behind Slippery Elm Bark 1,600 mg’s Ingredients

Every ingredient we hold a full HelloPharmacist monograph for — uses, evidence, safety, and the complete interaction list.

Herb & supplement monograph

Black Psyllium

Interacts with 2,025 drugs

Black psyllium is a soluble-fiber supplement made from the seeds of a Plantago plant, used mostly to ease constipation and support digestive health. It is best known and most studied for rel...

Read the full Black Psyllium monograph → Herb & supplement monograph

Slippery Elm

Interacts with 2,022 drugs

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 an...

Read the full Slippery Elm monograph →
Sources

Sources & How We Checked

Slippery Elm Bark 1,600 mg's label data comes from the NIH Dietary Supplement Label Database; the ingredient interaction data is from the Natural Medicines database, reviewed by our pharmacists.

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

The 21 references behind this product’s interaction data

Every citation that drives the interaction findings for this product’s ingredients, from the evidence-graded Natural Medicines (TRC Healthcare) database. Open an ingredient to browse its citations — links open the study on PubMed or the publisher’s site.

Black Psyllium 18 references
  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. Covington TR, et al. Handbook of Nonprescription Drugs. 11th ed. Washington, DC: American Pharmaceutical Association, 1996.
  4. Etman M. Effect of a bulk forming laxative on the bioavailablility of carbamazepine in man. Drug Dev Ind Pharm 1995;21:1901-6.
  5. Perlman BB. Interaction between lithium salts and ispaghula husk. Lancet 1990;335:416.
  6. Vaswani SK, Hamilton RG, Valentine MD, Adkinson NF. Psyllium laxative-induced anaphylaxis, asthma, and rhinitis. Allergy 1996;51:266-8. PubMed
  7. Lantner RR, Espiritu BR, Zumerchik P, Tobin MC. Anaphylaxis following ingestion of a psyllium-containing cereal. JAMA 1990;264:2534-6. DOI
  8. Kaplan MJ. Anaphylactic reaction to "Heartwise." N Engl J Med 1990;323:1072-3. DOI
  9. Nordstrom M, Melander A, Robertsson E, Steen B. Influence of wheat bran and of a bulk-forming ispaghula cathartic on the bioavailability of digoxin in geriatric in-patients. Drug Nutr Interact 1987;5:67-9..
  10. Robinson DS, Benjamin DM, McCormack JJ. Interaction of warfarin and nonsystemic gastrointestinal drugs. Clin Pharmacol Ther 1971;12:491-5. PubMed
  11. Garcia JJ, Fernandez N, Diez MJ, et al. Influence of two dietary fibers in the oral bioavailability and other pharmacokinetic parameters of ethinyloestradiol. Contraception 2000;62:253-7. PubMed
  12. Fernandez N, Lopez C, Díez R, et al. Drug interactions with the dietary fiber Plantago ovata husk. Expert Opin Drug Metab Toxicol 2012;8(11):1377-86.
  13. Semen plantaginis in: WHO Monographs on Selected Medicinal Plants, volume 1. World Health Organization, Geneva, 1999. Available at http://apps.who.int/medicinedocs/en/d/Js2200e/. Accessed November 26, 1026.
  14. Code of Federal Regulations, Title 21 (21CFR 101.17). Food labeling warning, notice, and safe handling statements. Available at www.ecfr.gov/cgi-bin/text-idx?SID=20f647d3b74161501f46564b915b4048&mc=true&node=se21.2.101_117&rgn=div8. Accessed December 3, 2
  15. Code of Federal Regulations, Title 21 (21CFR 201.319). Specific labeling requirements - water-soluble gums, hydrophilic gums, and hydrophilic mucilloids. Available at www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfcfr/CFRSearch.cfm?fr=201.319. Accessed Dece
  16. Diez R, Garcia JJ, Diez MJ, Sierra M, Sahagun AM, Fernandez N. Influence of Plantago ovata husk (dietary fiber) on the bioavailability and other pharmacokinetic parameters of metformin in diabetic rabbits. BMC Complement Altern Med. 2017 Jun 7;17(1):298. PubMed
  17. Chiu AC, Sherman SI. Effects of pharmacological fiber supplements on levothyroxine absorption. Thyroid. 1998;8(8):667-71. PubMed
  18. Merrick C, Madden CA, Capurso NA. A Case of Blunted Orally Disintegrating Olanzapine Effect Due to Coadministered Psyllium. J Clin Psychiatry 2021;82(2):20cr13633. PubMed

See these in context on the Black Psyllium monograph →

Slippery Elm 3 references
  1. The Review of Natural Products by Facts and Comparisons. St. Louis, MO: Wolters Kluwer Co., 1999.
  2. Brinker F. Herb Contraindications and Drug Interactions. 2nd ed. Sandy, OR: Eclectic Medical Publications, 1998.
  3. Czarnecki D, Nixon R, Bekhor P, and et al. Delayed prolonged contact urticaria from the elm tree. Contact Dermatitis 1993;28:196-197. PubMed

See these in context on the Slippery Elm monograph →

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

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