Major interaction on record — check this product against your medications before combining. Based on 6 of 9 ingredients. Check your meds →
Dietary supplement

Fiber Flow Capsules Ingredients & Drug Interactions

by Wise Woman Herbals

Fiber Flow Capsules label
See full label image
Capsule Category: Fiber And Other Nutrients
Most serious interaction: Major
Clinical methodology reviewed by · Updated Sep 16, 2026 · Label data from the NIH DSLD
What is this page for?

First and foremost: checking Fiber Flow Capsules 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: Major

Fiber Flow Capsules is a dietary supplement by Wise Woman Herbals with 9 active ingredients. Its ingredients are commonly taken for poisoning and drug overdose (in emergency care), gas and bloating, upset stomach.Based on those ingredients, 2,156 medications have a known interaction with it, the most serious rated major. The ingredients most likely to interact are Marshmallow, Charcoal, Slippery Elm. Use the checker below to test your specific medication, or read the full HelloPharmacist Interaction Report.

Jump to a section

Check Your Meds Against Fiber Flow Capsules by Wise Woman Herbals

Ask about any prescription or over-the-counter medication and we check it for interactions with Fiber Flow Capsules by Wise Woman Herbals — and tell you which ingredient is responsible.

Pharmacist-reviewed data Checks every ingredient Answer in seconds
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HelloPharmacist Scorecard of Fiber Flow Capsules by Wise Woman Herbals

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 30, 2026

What’s inside

Low disclosure
Ingredient Transparency · database check
Low

Most active ingredients don't disclose an individual amount — you can't tell how much of each you're getting.

Why this rating?
  • The label discloses an exact amount for 0 of its 9 active ingredients.
  • “Proprietary Blend” is a proprietary blend — the label gives one combined amount (2,504 mg) without saying how much of each component you get.

Fiber Flow contains nine ingredients in a proprietary blend, including several that support digestive function. The product includes oat bran, activated charcoal, and slippery elm for bowel support, along with Oregon grape, yellow dock, marshmallow, fenugreek, and psyllium — traditional botanical ingredients used in herbal wellness formulas.

The capsule itself is vegetarian.

Does it work?

Moderate 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

This product doesn't appear to be marketed for a specific use, so we graded its ingredients' overall clinical evidence instead.

Moderate

Some clinical evidence supports its ingredients for:

Why this rating?
  • We looked at the product name, claims, and label statements and couldn't find a stated purpose to grade.
  • Since the label doesn't commit to one use, we graded the ingredients' overall clinical evidence instead.
  • On file: Poisoning — rated "Possibly Effective" (Activated Charcoal) (Natural Medicines).
  • On file: Psoriasis — rated "Possibly Effective" (Oregon Grape) (Natural Medicines).
  • On file: Sexual dysfunction — rated "Possibly Effective" (Fenugreek) (Natural Medicines).
  • On file: Diabetes — rated "Possibly Effective" (Fenugreek) (Natural Medicines).
  • On file: Sexual arousal — rated "Possibly Effective" (Fenugreek) (Natural Medicines).

The data on file doesn't establish strong evidence for most of these ingredients in a fiber supplement context. Activated charcoal is possibly effective for poisoning, but the other uses listed for it — from hangover relief to high cholesterol — lack reliable evidence.

Oregon grape is possibly effective for psoriasis when used topically, but oral evidence for digestive uses is insufficient. Slippery elm, yellow dock, marshmallow, and fenugreek all show insufficient evidence for the digestive and bowel conditions you'd expect in a fiber product, though fenugreek does show possibly effective evidence for sexual dysfunction and blood sugar control in diabetes.

If you're looking for fiber supplement research, the strength of these particular ingredients isn't well established in the data we hold.

The evidence, ingredient by ingredient Activated Charcoal Oregon Grape Slippery Elm Yellow Dock Marshmallow Fenugreek

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 5 of the 6 matched ingredients.
  • Pregnancy & breastfeeding safety ratings cover 6 of 6.
  • General safety write-ups exist for 6 of 6.
  • Remember: this measures how much safety information exists. Thin data is not the same as being safe.

These ingredients are generally well tolerated for short-term use, but several carry cautions. Activated charcoal commonly causes constipation, black stools, bloating, and abdominal discomfort — and rarely can cause bowel obstruction.

Yellow dock and fenugreek work as mild laxatives, which may cause cramping and diarrhea. Fenugreek can trigger allergic reactions including swelling, wheezing, and in rare cases severe reactions like bronchospasm.

Oregon grape and slippery elm have limited safety data for routine oral use. For pregnancy and breastfeeding: Oregon grape is likely unsafe — berberine compounds cross into breast milk and may affect the developing uterus.

Yellow dock is possibly unsafe in pregnancy and lactation due to its laxative action. Fenugreek is likely unsafe in pregnancy but possibly safe while breastfeeding.

Marshmallow should be avoided in pregnancy and lactation due to insufficient safety data. Activated charcoal and slippery elm weren't well studied in pregnancy; talk with your doctor or pharmacist for personalized guidance.

No pregnancy or breastfeeding safety data is on file for oat bran, psyllium, or the full blend.

Side effects, ingredient by ingredient Activated Charcoal Oregon Grape Slippery Elm Yellow Dock Marshmallow Fenugreek

Meds to double-check

Major interaction found
Known Interaction Concern · database check
Major identified

At least one ingredient has a documented Major-severity interaction. Check your medications for a personalized result.

Why this rating?
  • 6 of the 6 matched ingredients can interact with medications — Activated Charcoal, Oregon Grape, Yellow Dock, Fenugreek, Marshmallow, among others.
  • The most serious interaction on file is rated Major.
  • Some involve high-stakes drug classes: anticoagulant / antiplatelet drugs; immunosuppressants / transplant drugs; diabetes medications; heart-rhythm medications; lithium.
  • For scale: 2,157 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.

Check before taking this if you use digoxin or diuretics (Major risk from yellow dock), oral medications in general (Major risk from activated charcoal), blood thinners including warfarin and clopidogrel, blood sugar medications, blood pressure drugs, heart rhythm medications like metoprolol, seizure medications like phenytoin, theophylline, sildenafil, or cyclosporine. No interactions are documented for oat bran and psyllium — we hold no data for those ingredients — but the other botanicals in the blend carry multiple Moderate-severity concerns.

Check your own medication Run your meds through the checker above

The bottom line

Scorecard at a glanceFormula with limited ingredient disclosure with some supporting evidence behind its ingredients' uses. Major medication interactions have been identified, and safety information is well characterized.

This product combines several traditional botanicals with fiber-type ingredients and carries meaningful interactions with heart, blood pressure, blood thinning, and diabetes medications — plus digoxin and diuretics warrant particular caution. If you take any regular medications, check each one against our tool before starting.

Talk with your doctor or pharmacist about whether this blend suits your health picture and any other supplements or herbs you're using.

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

Assessment coverage: 6 of 9 active ingredients matched to our full ingredient reviews (monographs). Based on the product label dated May 24, 2023.

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 Fiber Flow Capsules, straight from the product label.

Brand Wise Woman Herbals
Barcode (UPC) 748840001060
Net contents 120 Capsule(s)
Market status On market
Date entered into DSLD May 24, 2023
DSLD ID 284825
Product type Fiber And Other Nutrients
Supplement form Capsule
Dietary claims / uses All Other
Intended target group(s) Adult (18 - 50 Years)
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 Fiber Flow Capsules by Wise Woman Herbals, 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:
3 Capsule(s)
Maximum serving Sizes:
4 Capsule(s)
Servings per container
30
UPC/BARCODE
748840001060
IngredientAmount% DV
Proprietary Blend2504 mg--
Oat Bran0 NP--
Charcoal0 NP--
Oregon Grape0 NP--
Slippery Elm0 NP--
Yellow Dock0 NP--
Marshmallow0 NP--
Fenugreek0 NP--
Psyllium0 NP--
Psyllium0 NP--

Other ingredients: Vegetarian Capsules

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.
Suggested/Recommended/Usage/Directions

Suggested use: Take 3-4 capsules, up to 4 times per day. Drink 8 oz. of water each time.

Precautions

Caution: Keep out of the reach of children.

Warning: Cancer and reproductive harm. Www.P65Warnings.ca.gov.

General Statements

Botanical formula

FDA Statement of Identity

Dietary Supplement

Storage

Store in a cool, dry area away from direct sunlight with lid tightly sealed.

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

See for yourself

Fiber Flow Capsules by Wise Woman Herbals label

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

Fiber Flow Capsules 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 Fiber Flow Capsules by Wise Woman Herbals

These are the 9 active ingredients this product is made of. Select any to open its full monograph.

Serving size3 Capsule(s) Dosage formCapsule Servings per container30 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.

Proprietary Blend

2504 mg per serving

Other (inactive) ingredients: Vegetarian Capsules. These complete the product’s ingredient list but are not active constituents.

Interaction report

Fiber Flow Capsules by Wise Woman Herbals Drug Interactions

Want to check YOUR meds against Fiber Flow Capsules?

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
2,156Drugs
2,022 Major 134 Moderate

Ingredients driving the most interactions

Marshmallow 2,040
Charcoal 2,027
Slippery Elm 2,022
Oregon Grape 1,218
Fenugreek 389

Individual Drug Interactions

The ingredients in Fiber Flow Capsules interact with 2,156 drugs. Click any drug to see the details.

6 of the 9 ingredients in Fiber Flow Capsules interact with drugs. Each result below shows which ingredient is responsible. Marshmallow Charcoal Slippery Elm Oregon Grape Fenugreek Yellow Dock

Each ingredient & the kinds of drugs it affects

For each ingredient in Fiber Flow Capsules 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.

Marshmallow3 drug types · 2,040 drugs

Lithium

Theoretically, due to potential diuretic effects, marshmallow might reduce excretion and increase levels of lithium.
Marshmallow is thought to have diuretic properties. To avoid lithium toxicity, the dose of lithium might need to be decreased when used with marshmallow.

Likelihood Probable Evidence D
Anticoagulant/Antiplatelet Drugs

Theoretically, marshmallow flower might have antiplatelet effects.
Animal research suggests that marshmallow flower extract has antiplatelet effects. However, the root and leaf of marshmallow, not the flower, are the plant parts most commonly found in dietary supplements. Theoretically, use of marshmallow flower with anticoagulant/antiplatelet drugs can have additive effects, and might increase the risk for bleeding in some patients.

Likelihood Unlikely Evidence D
Oral Drugs

Theoretically, mucilage in marshmallow might impair absorption of oral drugs.
Marshmallow contains mucilage which can affect oral drug absorption. To avoid changes in absorption, take marshmallow 30-60 minutes after oral medications.

Likelihood Possible Evidence D
Marshmallow full monograph & interactions

Charcoal3 drug types · 2,027 drugs

Oral Drugs

Activated charcoal reduces systemic exposure to many drugs, including those that undergo enterohepatic recirculation, regardless of the route of administration.
Activated charcoal adsorbs various drugs and may reduce their absorption and/or half-life. Examples of affected drugs include acetaminophen, aminophylline, amiodarone, atenolol, carbamazepine, dapsone, digoxin, disopyramide, fluoxetine, indomethacin, moxifloxacin, nadolol, phenytoin, phenobarbital, piroxicam, quinine, sotalol, theophylline, tricyclic antidepressants, valproate, and verapamil. Avoid co-administration, except after drug overdose.

Likelihood Probable Evidence B
Alcohol (Ethanol)

The binding action of activated charcoal may be reduced by alcohol.
Alcohol may lower the adsorptive capacity of activated charcoal.

Likelihood Probable Evidence D
Contraceptive Drugs

Activated charcoal may reduce the clinical effects of oral contraceptives.
Activated charcoal, taken in a dose of 5 grams four times daily for 3 days, may bind to, and reduce the absorption of, oral contraceptives, thereby limiting their effectiveness and increasing the risk of contraceptive failure. However, some clinical research shows that the risk for this interaction is minimal when activated charcoal is taken either 3 hours after or at least 12 hours before oral contraceptives.

Likelihood Possible Evidence B
Charcoal 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

Oregon Grape9 drug types · 1,218 drugs

Anticoagulant/Antiplatelet Drugs

Theoretically, Oregon grape might increase the risk of bleeding when taken with anticoagulant or antiplatelet drugs.
In vitro and in vivo research suggests that berberine, a constituent of Oregon grape, can inhibit platelet aggregation.

Likelihood Possible Evidence D
Antidiabetes Drugs

Theoretically, Oregon grape might increase the risk of hypoglycemia when taken with antidiabetes drugs.
Clinical research suggests that berberine, a constituent of Oregon grape, can lower blood glucose levels.

Likelihood Possible Evidence A
Antihypertensive Drugs

Theoretically, Oregon grape might increase the risk of hypotension when taken with antihypertensive drugs.
Animal research suggests that berberine, a constituent of Oregon grape, can have hypotensive effects. Also, an analysis of clinical evidence suggests that taking berberine in combination with amlodipine (Norvasc) can lower systolic and diastolic blood pressure when compared with taking amlodipine alone.

Likelihood Possible Evidence D
Cns Depressants

Theoretically, Oregon grape might increase the sedative effects of CNS depressants.
Animal research suggests that berberine, a constituent of Oregon grape, can have sedative effects.

Likelihood Possible Evidence D
Cyclosporine (Neoral, Sandimmune)

Theoretically, Oregon grape might increase the effects and adverse effects of cyclosporine.
Berberine, a constituent of Oregon grape, can reduce metabolism of cyclosporine and increase serum levels. It might inhibit cytochrome P450 3A4 (CYP3A4), which metabolizes cyclosporine.

Likelihood Possible Evidence D
Cytochrome P450 2C9 (Cyp2C9) Substrates

Theoretically, Oregon grape might increase serum levels of drugs metabolized by CYP2C9.
Preliminary clinical evidence suggests that berberine, a constituent of Oregon grape, can inhibit cytochrome P450 2C9 (CYP2C9).

Likelihood Possible Evidence B
Cytochrome P450 2D6 (Cyp2D6) Substrates

Theoretically, Oregon grape might increase serum levels of drugs metabolized by CYP2D6.
In vitro research and preliminary clinical evidence suggest that berberine, a constituent of Oregon grape, can inhibit cytochrome P450 2D6 (CYP2D6).

Likelihood Possible Evidence B
Cytochrome P450 3A4 (Cyp3A4) Substrates

Theoretically, Oregon grape might increase serum levels of drugs metabolized by CYP3A4.
In vitro research and preliminary clinical evidence suggest that berberine, a constituent of Oregon grape, moderately inhibits cytochrome P450 3A4 (CYP3A4).

Likelihood Possible Evidence D
P-Glycoprotein Substrates

Theoretically, Oregon grape might increase serum levels of drugs that are P-glycoprotein (P-gp) substrates.
In vitro research suggests that Oregon grape extracts inhibit P-gp efflux.

Likelihood Possible Evidence D
Oregon Grape full monograph & interactions

Fenugreek9 drug types · 389 drugs

Anticoagulant/Antiplatelet Drugs

Theoretically, fenugreek might have additive effects when used with anticoagulant or antiplatelet drugs.
Some of the constituents in fenugreek have antiplatelet effects in animal and in vitro research. However, common fenugreek products might not contain sufficient concentrations of these constituents for clinical effects. A clinical study in patients with coronary artery disease or diabetes shows that taking fenugreek seed powder 2.5 grams twice daily for 3 months does not affect platelet aggregation, fibrinolytic activity, or fibrinogen levels .

Likelihood Unlikely Evidence B
Antidiabetes Drugs

Theoretically, fenugreek seed might have additive hypoglycemic effects when used with antidiabetes drugs.
Clinical research shows that fenugreek seed can reduce fasting blood glucose and 2-hour postprandial glucose levels in adults with type 2 diabetes.

Likelihood Probable Evidence B
Clopidogrel (Plavix)

Theoretically, fenugreek seed might alter the clinical effects of clopidogrel by inhibiting its conversion to the active form.
Animal research shows that fenugreek seed 200 mg/kg daily for 14 days increases the maximum serum concentration of clopidogrel by 21%. It is unclear how this affects the pharmacokinetics of the active metabolite of clopidogrel; however, this study found that concomitant use of fenugreek seed and clopidogrel prolonged bleeding time by an additional 11%.

Likelihood Possible Evidence D
Metoprolol (Toprol)

Theoretically, fenugreek seed might have additive hypotensive effects when used with metoprolol.
Animal research shows that fenugreek seed 300 mg/kg daily for 2 weeks decreases systolic and diastolic blood pressure by 9% and 11%, respectively, when administered alone, and by 15% and 22%, respectively, when given with metoprolol 10 mg/kg.

Likelihood Probable Evidence B
Phenytoin (Dilantin)

Theoretically, fenugreek might decrease plasma levels of phenytoin.
Animal research shows that taking fenugreek seeds for 1 week decreases maximum concentrations and the area under the curve of a single dose of phenytoin by 44% and 72%, respectively. This seems to be related to increased clearance. So far, this interaction has not been reported in humans.

Likelihood Possible Evidence D
Sildenafil (Viagra)

Theoretically, concurrent use of sildenafil and fenugreek might reduce levels and therapeutic effects of sildenafil.
Animal research shows that taking fenugreek seeds for 1 week reduces maximum concentrations and the area under the curve of a single dose of sildenafil by 27% and 48%, respectively. So far, this interaction has not been reported in humans.

Likelihood Possible Evidence D
Theophylline

Theoretically, fenugreek may reduce the levels and clinical effects of theophylline.
Animal research shows that fenugreek 50 grams daily for 7 days reduces the maximum serum concentration (Cmax) of theophylline by 28% and the area under the plasma drug concentration-time curve (AUC) by 22%.

Likelihood Possible Evidence D
Warfarin (Coumadin)

Theoretically, fenugreek might have additive effects with warfarin and increase the international normalized ratio (INR).
Some fenugreek constituents have antiplatelet effects, although these might not be present in concentrations that are clinically significant. In one case report, a patient taking warfarin experienced an increased INR when starting to take fenugreek in combination with boldo.

Likelihood Possible Evidence D
Antihypertensive Drugs

Fenugreek may also have an additive effect on blood pressure-lowering medications. Studies on animals have shown that fenugreek seed can decrease both systolic and diastolic blood pressure by up to 22% when combined with metoprolol. Therefore, it is essential to monitor your blood pressure regularly if you are taking fenugreek and metoprolol together or any other antihypertensive drugs.

Likelihood Possible Evidence C
Fenugreek full monograph & interactions

Yellow Dock3 drug types · 78 drugs

Digoxin (Lanoxin)

Theoretically, yellow dock might increase the risk of digoxin toxicity when used long-term or in large amount.
When yellow dock is used chronically or in large amounts, hypokalemia may occur. This might increase the toxic effects of digoxin.

Likelihood Probable Evidence D
Diuretic Drugs

Theoretically, yellow dock might increase the risk of hypokalemia when taken with diuretics.
When yellow dock is used chronically or in large amounts, hypokalemia may occur, and overuse of yellow dock might compound diuretic-induced potassium loss.

Likelihood Probable Evidence D
Warfarin (Coumadin)

Theoretically, the laxative effects of yellow dock might increase the effects of warfarin, including the risk of bleeding.
The anthraquinones in yellow dock have a mild stimulant laxative effect. Consuming excessive amounts can cause diarrhea. Diarrhea can increase the effects of warfarin, increase international normalized ratio (INR), and increase the risk of bleeding.

Likelihood Possible Evidence D
Yellow Dock full monograph & interactions
The maker

Brand information

Manufacturer and brand details for Fiber Flow Capsules, from the product label.

Wise Woman Herbals

See all Wise Woman Herbals products
Name
Wise Woman Herbals
City
Creswell
State
OR
ZipCode
97426
Phone Number
541.895.5152
Web Address
wisewomanherbals.com
Pharmacist Counseling Corner

Fiber Flow Capsules by Wise Woman Herbals: Common Questions

Does Fiber Flow Capsules by Wise Woman Herbals interact with any medications?
Yes. Based on its ingredients, Fiber Flow Capsules has a known interaction with 2,156 medications, including 2022 rated major. Use the checker to see how it interacts with a specific drug.
How can one product interact with so many drugs?
Fiber Flow Capsules contains 9 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 this reduce how well my other medications work?
Yes, it may. Activated charcoal can significantly lower absorption of many oral drugs, and slippery elm may slow drug absorption too. Oregon grape can interfere with how your liver processes certain medications. The timing and specific drug matter — use our search tool with your actual prescriptions to see what applies to you, then talk with your pharmacist or doctor before starting.
Is it safe to take while pregnant or breastfeeding?
No, not safely across the board. Oregon grape is likely unsafe — berberine passes into breast milk. Yellow dock is possibly unsafe in both pregnancy and lactation. Fenugreek is likely unsafe in pregnancy. Marshmallow lacks enough safety data for either. For activated charcoal, slippery elm, oat bran, and psyllium, the pregnancy and breastfeeding data aren't clear — talk with your doctor or pharmacist before using this product if you're pregnant or nursing.
What side effects should I expect?
Constipation and black stools are most common from the charcoal. You may also notice bloating, abdominal pain, or diarrhea as the product works as a mild laxative. Fenugreek can cause nausea, gas, and abdominal discomfort. Rare but serious effects include bowel obstruction and allergic reactions like swelling and wheezing.
Why does this product have so many ingredients?
They're combined in a proprietary blend — a mix of fiber sources (oat bran, psyllium) and traditional herbs (slippery elm, marshmallow, fenugreek, Oregon grape, yellow dock) meant to support digestive wellness. Activated charcoal is often added to herbal formulas for its absorptive properties. The exact amount of each ingredient isn't listed separately.
Is there good evidence this works for constipation or digestion?
The evidence isn't strong on file. None of the main ingredients — slippery elm, yellow dock, marshmallow, fenugreek, Oregon grape — have reliable evidence for constipation, diarrhea, or digestive problems. Activated charcoal is studied for poisoning, not routine fiber support. The oat bran and psyllium may help with fiber intake, but we hold no interaction or effectiveness data for those.
Can I take this around the same time as my other medications?
Probably not, and not for everything. Activated charcoal and slippery elm can reduce drug absorption — you'd need to space them apart, typically 30 to 60 minutes after your medications. Oregon grape and fenugreek interact with how your liver processes certain drugs. Your pharmacist or doctor can advise on timing and whether this product works with your specific regimen.

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

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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.

Fiber Flow Capsules label
Go deeper

The Full Monographs Behind Fiber Flow Capsules’s Ingredients

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

Herb & supplement monograph

Activated Charcoal

Interacts with 2,027 drugs

Activated charcoal is a highly porous form of carbon that can bind certain substances in the gut, and it is used in hospitals to treat some poisonings and overdoses. For everyday uses like g...

Read the full Activated Charcoal monograph → Herb & supplement monograph

Oregon Grape

Interacts with 1,218 drugs

Oregon grape is a shrub whose root contains berberine and related compounds. The strongest (though still modest) evidence is for topical creams that may slightly ease psoriasis; evidence for...

Read the full Oregon Grape 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 → Herb & supplement monograph

Yellow Dock

Interacts with 78 drugs

Yellow dock is a traditional herb used mostly as a mild laxative and a digestive and skin tonic. Good-quality human studies are lacking, so its benefits are largely unproven, and its natural...

Read the full Yellow Dock monograph → Herb & supplement monograph

Marshmallow

Interacts with 2,040 drugs

Marshmallow root is a traditional herb rich in soothing, gel-like fibers called mucilage, which is why it has long been used for coughs, sore throats, and stomach irritation. Evidence for th...

Read the full Marshmallow monograph → Herb & supplement monograph

Fenugreek

Interacts with 389 drugs

Fenugreek is a common kitchen spice that is also taken as a supplement, mainly for blood sugar, cholesterol, and to support breast milk production. Some early research is encouraging for blo...

Read the full Fenugreek monograph →
Sources

Sources & How We Checked

Fiber Flow Capsules'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 81 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.

Activated Charcoal 14 references
  1. Kaaja RJ, Kontula KK, Raiha A, Laatikainen T. Treatment of cholestasis of pregnancy with peroral activated charcoal. A preliminary study. Scand J Gastroenterol 1994;29:178-81.
  2. Anon. Position statement and practice guidelines on the use of multi-dose activated charcoal in the treatment of acute poisoning. American Academy of Clinical Toxicology; European Association of Poisons Centres and Clinical Toxicologists. J Toxicol Clin T
  3. Park GD, Spector R, Kitt TM. Superactivated charcoal versus cholestyramine for cholesterol lowering: a randomized cross-over trial. J Clin Pharmacol 1988;28:416-9. PubMed
  4. Hoegberg LC, Angelo HR, Christophersen AB, Christensen HR. Effect of ethanol and pH on the adsorption of acetaminophen (paracetamol) to high surface activated charcoal, in vitro studies. J Toxicol Clin Toxicol 2002;40:59-67. PubMed
  5. Brahmi N, Kouraichi N, Thabet H, Amamou M. Influence of activated charcoal on the pharmacokinetics and the clinical features of carbamazepine poisoning. Am J Emerg Med 2006;24(4):440-3. PubMed
  6. Gude AB, Hoegberg LC, Angelo HR, Christensen HR. Dose-dependent adsorptive capacity of activated charcoal for gastrointestinal decontamination of a simulated paracetamol overdose in human volunteers. Basic Clin Pharmacol Toxicol 2010;106(5)406-10. PubMed
  7. Wananukul W, Klaikleun S, Sriapha C, Tongpoo A. Effect of activated charcoal in reducing paracetamol absorption at supra-therapeutic dose. J Med Assoc Thai 2010;93(10):1145-9.
  8. Wang Z, Cui M, Tang L, et al. Oral activated charcoal suppresses hyperphosphataemia in haemodialysis patients. Nephrology (Carlton) 2012;17(7):616-20. PubMed
  9. Wang X, Mondal S, Wang J, et al. Effect of activated charcoal on apixaban pharmacokinetics in healthy subjects. Am J Cardiovasc Drugs 2014;14(2):147-54. PubMed
  10. Chyka PA, Seger D, Krenzelok EP, et al. Position paper: single-dose activated charcoal. Clin Toxicol (Phila) 2005;43(2):61-87. PubMed
  11. Chiew AL, Gluud C, Brok J, Buckley NA. Interventions for paracetamol (acetaminophen) overdose. Cochrane Database Syst Rev 2018;2:CD003328. PubMed
  12. Elomaa K, Ranta S, Tuominen J, Lähteenmäki P. Charcoal treatment and risk of escape ovulation in oral contraceptive users. Hum Reprod. 2001;16(1):76-81. PubMed
  13. Gao Y, Wang G, Li Y, Lv C, Wang Z. Effects of oral activated charcoal on hyperphosphatemia and vascular calcification in Chinese patients with stage 3-4 chronic kidney disease. J Nephrol. 2019;32(2):265-72. PubMed
  14. Skov K, Graudal NA, Jürgens G. The effect of activated charcoal on drug exposure following intravenous administration: A meta-analysis. Basic Clin Pharmacol Toxicol 2021;128(4):568-578. PubMed

See these in context on the Activated Charcoal monograph →

Oregon Grape 21 references
  1. Wiesenauer M, Lydtke R. Mahonia aquifolium in patients with Psoriasis vulgaris; an intraindividual study. Phytomedicine 1996;3:231-5.
  2. Chan E. Displacement of bilirubin from albumin by berberine. Biol Neonate 1993;63:201-8. PubMed
  3. Janbaz KH, Gilani AH. Studies on preventive and curative effects of berberine on chemical-induced hepatotoxicity in rodents. Fitoterapia 2000;71:25-33.. PubMed
  4. Wu X, Li Q, Xin H, Yu A, Zhong M. Effects of berberine on the blood concentration of cyclosporin A in renal transplanted recipients: clinical and pharmacokinetic study. Eur J Clin Pharmacol 2005;61:567-72. PubMed
  5. Gulliver WP, Donsky HJ. A report on three recent clinical trials using Mahonia aquifolium 10% topical cream and a review of the worldwide clinical experience with Mahonia aquifolium for the treatment of plaque psoriasis. Am J Ther 2005;12:398-406. PubMed
  6. Zhang Y, Li X, Zou D, et al. Treatment of type 2 diabetes and dyslipidemia with the natural plant alkaloid berberine. J Clin Endocrinol Metab 2008;93:2559-65. PubMed
  7. Budzinski JW, Foster BC, Vandenhoek S, Arnason JT. An in vitro evaluation of human cytochrome P450 3A4 inhibition by selected commercial herbal extracts and tinctures. Phytomedicine 2000;7:273-82. PubMed
  8. Chatterjee P, Franklin MR. Human cytochrome p450 inhibition and metabolic-intermediate complex formation by goldenseal extract and its methylenedioxyphenyl components. Drug Metab Dispos 2003;31:1391-7. PubMed
  9. Shanbhag, S. M., Kulkarni, H. J., and Gaitonde, B. B. Pharmacological actions of berberine on the central nervous system. Jpn.J Pharmacol 1970;20(4):482-487. PubMed
  10. Wu, J. F. and Liu, T. P. [Effects of berberine on platelet aggregation and plasma levels of TXB2 and 6-keto-PGF1 alpha in rats with reversible middle cerebral artery occlusion]. Yao Xue.Xue.Bao. 1995;30(2):98-102.
  11. Peng, W. H., Hsieh, M. T., and Wu, C. R. Effect of long-term administration of berberine on scopolamine-induced amnesia in rats. Jpn J Pharmacol 1997;74(3):261-266. DOI
  12. Sabir M and Bhide NK. Study of some pharmacological actions of berberine. Ind J Physiol & Pharmac 1971;15(3):111-132.
  13. Tripathi YB and Shukla SD. Berberis artistata inhibits PAF induced aggregation of rabbit platelets. Phytotherapy Research 1996;10:628-630.
  14. Yin, J., Xing, H., and Ye, J. Efficacy of berberine in patients with type 2 diabetes mellitus. Metabolism 2008;57(5):712-717. PubMed
  15. Zhang, H., Wei, J., Xue, R., Wu, J. D., Zhao, W., Wang, Z. Z., Wang, S. K., Zhou, Z. X., Song, D. Q., Wang, Y. M., Pan, H. N., Kong, W. J., and Jiang, J. D. Berberine lowers blood glucose in type 2 diabetes mellitus patients through increasing insulin re
  16. Guo, Y., Chen, Y., Tan, Z. R., Klaassen, C. D., and Zhou, H. H. Repeated administration of berberine inhibits cytochromes P450 in humans. Eur J Clin Pharmacol 2012;68(2):213-217. PubMed
  17. Wei, W., Zhao, H., Wang, A., Sui, M., Liang, K., Deng, H., Ma, Y., Zhang, Y., Zhang, H., and Guan, Y. A clinical study on the short-term effect of berberine in comparison to metformin on the metabolic characteristics of women with polycystic ovary syndro
  18. Hermann, R. and von, Richter O. Clinical evidence of herbal drugs as perpetrators of pharmacokinetic drug interactions. Planta Med 2012;78(13):1458-1477. PubMed
  19. Chun YT, Yip TT, Lau KL, and et al. A biochemical study on the hypotensive effect of berberine in rats. Gen Pharmac 1979;10:177-182. PubMed
  20. Lan J, Zhao Y, Dong F, et al. Meta-analysis of the effect and safety of berberine in the treatment of type 2 diabetes mellitus, hyperlipemia and hypertension. J Ethnopharmacol. 2015;161:69-81. PubMed
  21. Fan Y, Zhou Z, Zhang L. Effect of Oregon grape root extracts on P-glycoprotein mediated transport in in vitro cell lines. J Pharm Pharm Sci 2024;26:11927. PubMed

See these in context on the Oregon Grape 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 →

Yellow Dock 8 references
  1. Newall CA, Anderson LA, Philpson JD. Herbal Medicine: A Guide for Healthcare Professionals. London, UK: The Pharmaceutical Press, 1996.
  2. Foster S, Tyler VE. Tyler's Honest Herbal: A Sensible Guide to the Use of Herbs and Related Remedies. 3rd ed., Binghamton, NY: Haworth Herbal Press, 1993.
  3. The Review of Natural Products by Facts and Comparisons. St. Louis, MO: Wolters Kluwer Co., 1999.
  4. McGuffin M, Hobbs C, Upton R, Goldberg A, eds. American Herbal Products Association's Botanical Safety Handbook. Boca Raton, FL: CRC Press, LLC 1997.
  5. Ellenhorn MJ, et al. Ellenhorn's Medical Toxicology: Diagnoses and Treatment of Human Poisoning. 2nd ed. Baltimore, MD: Williams & Wilkins, 1997.
  6. Gruenwald J, Brendler T, Jaenicke C. PDR for Herbal Medicines. 1st ed. Montvale, NJ: Medical Economics Company, Inc., 1998.
  7. Brinker F. Herb Contraindications and Drug Interactions. 2nd ed. Sandy, OR: Eclectic Medical Publications, 1998.
  8. Latif A, Fichadiya H, Abid F, Capo G. Herbal Teas and Thrombocytopenia: A Curious Case of Yellow Dock and Burdock-Induced Thrombocytopenia. Eur J Case Rep Intern Med 2022;9(3):003247. PubMed

See these in context on the Yellow Dock monograph →

Marshmallow 5 references
  1. Monographs on the medicinal uses of plant drugs. Exeter, UK: European Scientific Co-op Phytother, 1997.
  2. Leung AY, Foster S. Encyclopedia of Common Natural Ingredients Used in Food, Drugs and Cosmetics. 2nd ed. New York, NY: John Wiley & Sons, 1996.
  3. McGuffin M, Hobbs C, Upton R, Goldberg A, eds. American Herbal Products Association's Botanical Safety Handbook. Boca Raton, FL: CRC Press, LLC 1997.
  4. Brinker F. Herb Contraindications and Drug Interactions. 2nd ed. Sandy, OR: Eclectic Medical Publications, 1998.
  5. Hage-Sleiman R, Mroueh M, Daher CF. Pharmacological evaluation of aqueous extract of Althaea officinalis flower grown in Lebanon. Pharm Biol 2011;49(3):327-33.

See these in context on the Marshmallow monograph →

Fenugreek 30 references
  1. Madar Z, Thorne R. Dietary fiber. Prog Food Nutr Sci 1987;11:153-74.
  2. Sharma RD, Raghuram TC, Rao NS. Effect of fenugreek seeds on blood glucose and serum lipids in type I diabetes. Eur J Clin Nutr 1990;44:301-6.
  3. Patil SP, Niphadkar PV, Bapat MM. Allergy to fenugreek (Trigonella foenum graecum). Ann Allergy Asthma Immunol 1997;78:297-300. PubMed
  4. Lambert J, Cormier J. Potential interaction between warfarin and boldo-fenugreek. Pharmacotherapy 2001;21:509-12. PubMed
  5. Bordia A, Verma SK, Srivastava KC. Effect of ginger (Zingiber officinale Rosc.) and fenugreek (Trigonella foenumgraecum L.) on blood lipids, blood sugar and platelet aggregation in patients with coronary artery disease. Prostaglandins Leukot Essent Fatty PubMed
  6. Yalcin SS, Tekinalp G, Ozalp I. Peculiar odor of traditional food and maple syrup urine disease. Pediatr Int 1999;41:108-9. PubMed
  7. Sewell AC, Mosandl A, Bohles H. False diagnosis of maple syrup urine disease owing to ingestion of herbal tea. N Engl J Med 1999;341:769.. PubMed
  8. Abdo MS, al-Kafawi AA. Experimental studies on the effect of Trigonella foenum-graecum (abstract). Planta Med 1969;17:14-8.
  9. Gupta A, Gupta R, Lal B. Effect of Trigonella foenum-graecum (fenugreek) seeds on glycaemic control and insulin resistance in type 2 diabetes mellitus: a double blind placebo controlled study. J Assoc Physicians India 2001;49:1057-61.
  10. Gabay MP. Galactogogues: medications that induce lactation. J Hum Lact 2002;18:274-9. PubMed
  11. Chevassus H, Gaillard JB, Farret A, et al. A fenugreek seed extract selectively reduces spontaneous fat intake in overweight subjects. Eur J Clin Pharmacol 2010;66(5):449-55. PubMed
  12. Turkyilmaz C, Onal E, Hirfanoglu IM, et al. The effect of galactagogue herbal tea on breast milk production and short-term catch-up of birth weight in the first week of life. J Altern Complement Med 2011;17(2):139-42. PubMed
  13. Swafford S, Berens P. Effect of fenugreek on breast milk volume. Abstract presented at: 5th International Meeting of the Academy of Breastfeeding Medicine; September 11-13,2000, Tucson, Arizona.
  14. Abdel-Barry, J. A., Abdel-Hassan, I. A., Jawad, A. M., and al Hakiem, M. H. Hypoglycaemic effect of aqueous extract of the leaves of Trigonella foenum-graecum in healthy volunteers. East Mediterr.Health J 2000;6(1):83-88. DOI
  15. Parvizpur, A., Ahmadiani, A., and Kamalinejad, M. Probable role of spinal purinoceptors in the analgesic effect of Trigonella foenum (TFG) leaves extract. J Ethnopharmacol 3-8-2006;104(1-2):108-112. PubMed
  16. Mora, A., Herrrera, A., Lopez, C., Dahbi, G., Mamani, R., Pita, J. M., Alonso, M. P., Llovo, J., Bernardez, M. I., Blanco, J. E., Blanco, M., and Blanco, J. Characteristics of the Shiga-toxin-producing enteroaggregative Escherichia coli O104:H4 German ou
  17. Blanco, J. [Stx2a-producing enteroaggregative Escherichia coli O104:H4-ST678. Microbiological diagnostic already, for this and other STEC/VTEC serotypes!]. Enferm.Infecc.Microbiol.Clin. 2012;30(2):84-89.
  18. Beutin, L. and Martin, A. Outbreak of Shiga toxin-producing Escherichia coli (STEC) O104:H4 infection in Germany causes a paradigm shift with regard to human pathogenicity of STEC strains. J Food Prot. 2012;75(2):408-418. PubMed
  19. King LA, Nogareda F, Weill FX, Mariani-Kurkdjian P, Loukiadis E, Gault G, Jourdan-DaSilva N, Bingen E, Macé M, Thevenot D, Ong N, Castor C, Noël H, Van Cauteren D, Charron M, Vaillant V, Aldabe B, Goulet V, Delmas G, Couturier E, Le Strat Y, Combe C, Delm
  20. Reeder C, Legrand A, O'Connor-Von SK. The Effect of Fenugreek on Milk Production and Prolactin Levels in Mothers of Preterm Infants. Clinical Lactation 2013;4(4):159-165. DOI
  21. Al-Jenoobi FI, Ahad A, Mahrous GM, Al-Mohizea AM, AlKharfy KM, Al-Suwayeh SA. Effects of fenugreek, garden cress, and black seed on theophylline pharmacokinetics in beagle dogs. Pharm Biol 2015;53(2):296-300. PubMed
  22. Rao A, Steels E, Inder WJ, Abraham S, Vitetta L. Testofen, a specialised Trigonella foenum-graecum seed extract reduces age-related symptoms of androgen decrease, increases testosterone levels and improves sexual function in healthy aging males in a doubl
  23. Steels E, Rao A, Vitetta L. Physiological aspects of male libido enhanced by standardized Trigonella foenum-graecum extract and mineral formulation. Phytother Res. 2011 Sep;25(9):1294-300.
  24. Gong J, Fang K, Dong H, Wang D, Hu M, Lu F. Effect of fenugreek on hyperglycaemia and hyperlipidemia in diabetes and prediabetes: A meta-analysis. J Ethnopharmacol. 2016 Dec 24;194:260-268. PubMed
  25. Ouzir M, El Bairi K, Amzazi S. Toxicological properties of fenugreek (Trigonella foenum graecum). Food Chem Toxicol. 2016 Oct;96:145-54. PubMed
  26. Khodamoradi K, Khosropanah MH, Ayati Z, et al. The Effects of Fenugreek on Cardiometabolic Risk Factors in Adults: A Systematic Review and Meta-analysis. Complement Ther Med. 2020;52:102416. PubMed
  27. Alkharfy K, Jan B, Alotaibi K, et al. Clopidogrel-herb Interactions: A Pharmacokinetic and Pharmacodynamic Assessment in a Rat Model. Curr Drug Metab 2021;22(12):969-977. PubMed
  28. Bin Jardan YA, Ahad A, Raish M, Alam MA, Al-Mohizea AM, Al-Jenoobi FI. Effects of garden cress, fenugreek and black seed on the pharmacodynamics of metoprolol: an herb-drug interaction study in rats with hypertension. Pharm Biol 2021;59(1):1088-1097. PubMed
  29. Al-Mohizea AM, Ahad A, El-Maghraby GM, et al. Effects of Nigella sativa, Lepidium sativum and Trigonella foenum-graecum on sildenafil disposition in beagle dogs. Eur J Drug Metab Pharmacokinet. 2015;40(2):219-24. PubMed
  30. Alkharfy KM, Al-Jenoobi FI, Al-Mohizea AM, et al. Effects of Lepidium sativum, Nigella sativa and Trigonella foenum-graceum on phenytoin pharmacokinetics in beagle dogs. Phytother Res. 2013;27(12):1800-4.

See these in context on the Fenugreek monograph →

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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.

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