Interactions on record — worth a quick check against your medications. Based on 5 of 6 ingredients. Check your meds →
Dietary supplement

Gastro-Fiber Ingredients & Drug Interactions

by SP Standard Process

Gastro-Fiber label
See full label image
Capsule Category: Botanical With Nutrients
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 Gastro-Fiber 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

Gastro-Fiber is a dietary supplement by SP Standard Process with 6 active ingredients. Its ingredients are commonly taken for constipation, diarrhea, high cholesterol.Based on those ingredients, 2,133 medications have a known interaction with it, the most serious rated moderate. The ingredients most likely to interact are Dietary Fiber, Fennel, Fenugreek. Use the checker below to test your specific medication, or read the full HelloPharmacist Interaction Report.

Jump to a section

Check Your Meds Against Gastro-Fiber by SP Standard Process

Ask about any prescription or over-the-counter medication and we check it for interactions with Gastro-Fiber by SP Standard Process — and tell you which ingredient is responsible.

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HelloPharmacist Scorecard of Gastro-Fiber by SP Standard Process

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 1 of its 6 active ingredients.
  • “Proprietary Blend” is a proprietary blend — the label gives one combined amount (1,250 mg) without saying how much of each component you get.

Gastro-Fiber contains five active ingredients. Psyllium is a soluble fiber that absorbs water to add bulk to stool.

The proprietary blend comprises fenugreek seed, fennel, apple pectin, and collinsonia (stone root)—each a traditional botanical for digestive support. The product also contains inactive ingredients: cellulose, calcium stearate, and water.

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

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

Strong

Strong 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: Constipation — rated "Effective" (Black Psyllium) (Natural Medicines).
  • On file: Coronary heart disease (CHD) — rated "Likely Effective" (Black Psyllium) (Natural Medicines).
  • On file: Dysmenorrhea — rated "Possibly Effective" (Fennel) (Natural Medicines).
  • On file: Hypercholesterolemia — rated "Possibly Effective" (Pectin) (Natural Medicines).
  • On file: Sexual dysfunction — rated "Possibly Effective" (Fenugreek) (Natural Medicines).

The evidence for these ingredients is limited and mixed. Fenugreek shows possibly effective evidence for sexual dysfunction and diabetes support, and fennel is possibly effective for dysmenorrhea (period pain).

Apple pectin is possibly effective for high cholesterol. For other uses in this blend—such as general digestive support or the role of psyllium, fennel for anxiety or bronchitis, or collinsonia—either the evidence is insufficient or we hold no rating data.

The evidence, ingredient by ingredient Black Psyllium Fenugreek Fennel Pectin Stone Root

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

Fenugreek is generally well tolerated in food amounts, but supplement doses can cause abdominal pain, bloating, diarrhea, indigestion, gas, and nausea; rare severe allergic reactions including anaphylaxis have been reported. Fennel also appears well tolerated orally and topically as a food, though concentrated supplements may cause gastrointestinal discomfort, sensitivity to sunlight, and rare seizures.

Apple pectin is generally well tolerated, with the most common side effects being gas, loose stools, and mild cramps; rare allergic reactions including anaphylaxis have occurred. Collinsonia has little safety data; large amounts may cause intestinal irritation, cramping, dizziness, and nausea.

Fenugreek in medicinal amounts should be avoided in pregnancy, and fennel medicinal use is possibly unsafe in pregnancy due to hormone-like effects. Both fenugreek and fennel have uncertain safety during breastfeeding at supplement doses—food amounts are more reassuring—while pectin appears likely safe.

Collinsonia safety in pregnancy and breastfeeding is unknown; avoid it during these times.

Side effects, ingredient by ingredient Black Psyllium Fenugreek Fennel Pectin Stone Root

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?
  • 4 of the 5 matched ingredients can interact with medications — Black Psyllium, Fennel, Pectin, Fenugreek.
  • The most serious interaction on file is rated Moderate.
  • Some involve high-stakes drug classes: anticoagulant / antiplatelet drugs; diabetes medications; heart-rhythm medications; lithium.
  • For scale: 2,134 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 product if you use blood thinners or antiplatelet drugs (warfarin, clopidogrel, aspirin), diabetes medications, theophylline, metoprolol, phenytoin, sildenafil, contraceptive pills, any drug your liver breaks down via CYP3A4, estrogen replacement, ciprofloxacin, tamoxifen, lovastatin, tetracycline antibiotics, or digoxin. These are Moderate-severity interactions.

No interactions are documented for psyllium.

Check your own medication Run your meds through the checker above

The bottom line

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

Gastro-Fiber is built on traditional digestive botanicals with modest evidence for some uses, but it carries real interaction risks, especially if you take blood thinners, diabetes drugs, heart or blood pressure medications, or certain antibiotics. If you're pregnant or breastfeeding, talk to your doctor or pharmacist first—some ingredients are not recommended.

Before you start, check your medications against the tool on this page, and discuss the results with your own healthcare provider.

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

Assessment coverage: 5 of 6 active ingredients matched to our full ingredient reviews (monographs). Based on the product label dated Nov 19, 2021.

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 Gastro-Fiber, straight from the product label.

Brand SP Standard Process
Barcode (UPC) 812122011006
Net contents 150 Capsule(s)
Market status On market
Date entered into DSLD Nov 19, 2021
DSLD ID 256521
Product type Botanical With Nutrients
Supplement form Capsule
Dietary claims / uses All Other
Intended target group(s) Adult (18 - 50 Years), Gluten 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 Gastro-Fiber by SP Standard Process, 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:
3 Capsule(s)
Servings per container
50
UPC/BARCODE
812122011006
IngredientAmount% DV
Calories5 Calories--
Total Carbohydrates1 Gram(s)1%
Dietary Fiber0.5 Gram(s)2%
Psyllium0 NP--
Proprietary Blend1250 mg--
Fenugreek0 NP--
Fennel0 NP--
Apple Pectin0 NP--
Collinsonia0 NP--

Other ingredients: Cellulose, Calcium Stearate, Water

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.
FDA Statement of Identity

Dietary Supplement

Suggested/Recommended/Usage/Directions

Suggested Use: Three capsules, three times per day on an empty stomach, or as directed.

Formulation

Gluten free

General Statements

Whole Food Supplements Since 1929

Precautions

Caution: If pregnant or lactating, consult your health care professional before using this product.

This product is processed in a facility that manufactures other products containing soy, milk, egg, wheat, peanut, tree nuts, fish, and shellfish.

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

See for yourself

Gastro-Fiber by SP Standard Process label

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

Gastro-Fiber 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 Gastro-Fiber by SP Standard Process

These are the 6 active ingredients this product is made of. Select any to open its full monograph.

Serving size3 Capsule(s) Dosage formCapsule Servings per container50 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
0.5 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

Proprietary Blend

1250 mg per serving

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

Interaction report

Gastro-Fiber by SP Standard Process Drug Interactions

Want to check YOUR meds against Gastro-Fiber?

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
2,133Drugs
855 Moderate 1,278 Minor

Ingredients driving the most interactions

Dietary Fiber 2,025
Fennel 740
Fenugreek 389
Apple Pectin 23

Individual Drug Interactions

The ingredients in Gastro-Fiber interact with 2,133 drugs. Click any drug to see the details.

4 of the 6 ingredients in Gastro-Fiber interact with drugs. Each result below shows which ingredient is responsible. Dietary Fiber Fennel Fenugreek Apple Pectin

Each ingredient & the kinds of drugs it affects

For each ingredient in Gastro-Fiber 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

Fennel6 drug types · 740 drugs

Anticoagulant/Antiplatelet Drugs

Theoretically, fennel might increase the risk of bleeding when used with antiplatelet or anticoagulant drugs.

Animal research suggests that fennel oil has antithrombotic and antiplatelet effects.

Likelihood Possible Evidence D
Ciprofloxacin (Cipro)

Theoretically, fennel might decrease the levels and clinical effects of ciprofloxacin.

Animal research shows that fennel reduces ciprofloxacin bioavailability by nearly 50%, possibly due to the metal cations such as calcium, iron, and magnesium contained in fennel. This study also found that fennel increased tissue distribution and slowed elimination of ciprofloxacin.

Likelihood Probable Evidence D
Contraceptive Drugs

Theoretically, taking large amounts of fennel might decrease the effects of contraceptive drugs due to competition for estrogen receptors.

Some constituents of fennel have estrogenic activity.

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

Theoretically, fennel might increase levels of drugs metabolized by CYP3A4.

In vitro research suggests that fennel inhibits CYP3A4 enzyme activity. This effect has not been reported in humans.

Likelihood Possible Evidence D
Estrogens

Theoretically, taking large amounts of fennel might interfere with hormone replacement therapy due to competition for estrogen receptors.

Some constituents of fennel have estrogenic activity.

Likelihood Possible Evidence D
Tamoxifen (Nolvadex)

Theoretically, taking large amounts of fennel might decrease the antiestrogenic effect of tamoxifen.

Some constituents of fennel have estrogenic activity, which may interfere with the antiestrogenic activity of tamoxifen.

Likelihood Possible Evidence D
Fennel 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

Apple Pectin3 drug types · 23 drugs

Digoxin (Lanoxin)

Theoretically, pectin might reduce the absorption of digoxin, potentially decreasing its effectiveness.
A small clinical study shows that taking digoxin with a kaolin-pectin suspension reduces the absorption of digoxin by about 62%. It is unclear if these effects are due to pectin, kaolin, or the combination.

Likelihood Possible Evidence B
Lovastatin (Mevacor)

Theoretically, pectin might reduce the absorption of lovastatin, potentially decreasing its effectiveness.
Case reports suggest that concomitant use of pectin and lovastatin might reduce the cholesterol-lowering effect of lovastatin, possibly due to reduced intestinal absorption of lovastatin.

Likelihood Possible Evidence D
Tetracycline Antibiotics

Theoretically, pectin might reduce the absorption of tetracycline antibiotics, potentially decreasing their effectiveness.
A small clinical study shows that taking tetracycline with bismuth subsalicylate in a kaolin-pectin suspension reduces the absorption of tetracycline by about 34%. It is unclear if these effects are due to pectin, kaolin, bismuth subsalicylate, or the combination.

Likelihood Possible Evidence B
Apple Pectin full monograph & interactions
The maker

Brand information

Manufacturer and brand details for Gastro-Fiber, from the product label.

SP Standard Process

See all SP Standard Process products
Name
Standard Process Inc.
Street Address
1200 West Royal Lee Drive
City
Palmyra
State
WI
ZipCode
53156
Pharmacist Counseling Corner

Gastro-Fiber by SP Standard Process: Common Questions

Does Gastro-Fiber by SP Standard Process interact with any medications?
Yes. Based on its ingredients, Gastro-Fiber has a known interaction with 2,133 medications. Use the checker to see how it interacts with a specific drug.
How can one product interact with so many drugs?
Gastro-Fiber contains 6 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.
Can I take Gastro-Fiber if I'm on a blood thinner like warfarin?
Not without checking first. Fenugreek in this product may have blood-thinning effects that could add to warfarin's action. Talk to your doctor or pharmacist before starting; they can assess your individual risk and may want to monitor you more closely.
Will this affect my diabetes medication?
Possibly. Fenugreek has been shown to lower blood sugar in clinical studies, so taking it with diabetes drugs could push your levels too low. Your doctor or pharmacist should review this interaction with you and may want to adjust your monitoring.
Is Gastro-Fiber safe during pregnancy?
No. Fenugreek and fennel are not recommended in medicinal amounts during pregnancy. The safety data advises against it. Talk to your doctor or pharmacist before considering it if you're pregnant or planning to become pregnant.
What are the most common side effects I might notice?
From fenugreek, fennel, and pectin combined, the most common are gas, bloating, diarrhea, indigestion, and nausea. Collinsonia in large amounts may add intestinal cramping, dizziness, and nausea. These usually occur when you first start or take higher doses.
Does this product actually work for digestive problems?
The evidence is limited. Fenugreek and fennel show possibly effective ratings for specific uses—fenugreek for sexual dysfunction and diabetes, fennel for period pain—but we don't have established evidence for general digestive support with this blend as a whole.
Can I take this while breastfeeding?
It's uncertain. Fenugreek is sometimes used to boost milk supply, but evidence is limited and you should discuss it with your provider first. Fennel and collinsonia safety while breastfeeding has not been well studied at supplement doses. Food amounts of these ingredients are more reassuring.

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.

Gastro-Fiber label
Go deeper

The Full Monographs Behind Gastro-Fiber’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

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 → Herb & supplement monograph

Fennel

Interacts with 740 drugs

Fennel is a Mediterranean herb widely used as a food and spice, and traditionally taken for digestive complaints, colic, and menstrual cramps. Some small studies suggest possible benefit for...

Read the full Fennel monograph → Herb & supplement monograph

Pectin

Interacts with 23 drugs

Pectin is a natural soluble fiber found in fruits like apples and citrus, and it is widely used in foods and as a fiber supplement. It may modestly help with cholesterol, blood sugar, and di...

Read the full Pectin monograph → Herb & supplement monograph

Stone Root

Stone root is a North American herb traditionally used for hemorrhoids, urinary complaints, and digestive issues. There is very little modern scientific evidence to confirm it works for any...

Read the full Stone Root monograph →
Sources

Sources & How We Checked

Gastro-Fiber'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 77 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 →

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
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Fennel 17 references
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Pectin 11 references
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See these in context on the Pectin monograph →

Stone Root 1 reference
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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.

© 2021 Therapeutic Research Center, LLC

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