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Dietary supplement

Fennel Seed 480 mg Ingredients & Drug Interactions

by Nature's Way

Fennel Seed 480 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 Fennel Seed 480 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

Fennel Seed 480 mg is a dietary supplement by Nature's Way with 1 active ingredient. Its ingredients are commonly taken for digestive upset and bloating, infant colic, menstrual cramps.Based on those ingredients, 740 medications have a known interaction with it, the most serious rated moderate. The ingredients most likely to interact are Fennel. Use the checker below to test your specific medication, or read the full HelloPharmacist Interaction Report.

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Check Your Meds Against Fennel Seed 480 mg by Nature's Way

Ask about any prescription or over-the-counter medication and we check it for interactions with Fennel Seed 480 mg by Nature's Way — and tell you which ingredient is responsible.

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HelloPharmacist Scorecard of Fennel Seed 480 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 30, 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 1 of its 1 active ingredient.
  • No proprietary blends here — you can verify the dose of every single component.

This product contains one active ingredient: fennel seed at 480 mg per capsule. Fennel is a plant seed used in traditional herbal practice for digestive and respiratory support.

The capsule itself is plant-derived, and the formula includes silica as an inactive ingredient.

Does it work?

Not established
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
Not established

The graded evidence we hold for these ingredients covers different conditions than the ones this product is marketed for, so there's no established rating for its stated use — see Fennel's own graded uses on its monograph.

Why this rating?
  • The label markets this product for: helps sweeten breath and aids digestion.
  • We looked for evidence on: Dyspepsia, Flatulence, Colic, halitosis, indigestion.
  • The closest evidence on file: Fennel is rated "Insufficient Reliable Evidence To Rate" for Dyspepsia (Natural Medicines).
  • Also on file: Fennel is rated "Insufficient Reliable Evidence To Rate" for Flatulence, Colic.

In our data, fennel is rated possibly effective for dysmenorrhea (painful menstrual periods). For bronchitis, anxiety, nocturnal enuresis (bedwetting), and cholera, we hold insufficient reliable evidence to rate its effectiveness.

If you're considering this supplement for one of those other uses, talk with your doctor or pharmacist about whether the evidence supports it for your situation.

The evidence, ingredient by ingredient Fennel

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 1 of the 1 matched ingredient.
  • Pregnancy & breastfeeding safety ratings cover 1 of 1.
  • General safety write-ups exist for 1 of 1.
  • Remember: this measures how much safety information exists. Thin data is not the same as being safe.

Fennel is generally well tolerated when taken by mouth or applied to skin. The most common side effects are gastrointestinal discomfort, photosensitivity (increased sun sensitivity), and allergic reactions in sensitive individuals.

Serious side effects are rare but seizures have been reported. Allergic reactions can be severe—one case involved breathing difficulty and palpitations after fennel toothpaste exposure.

During pregnancy, concentrated fennel supplements are rated possibly unsafe due to limited safety data and hormone-like effects; food amounts are likely okay, but medicinal doses should be avoided. While breastfeeding, food amounts are probably fine, but medicinal doses and fennel essential oil are not well studied.

Talk with your doctor or pharmacist before use if you're pregnant or nursing.

Side effects, ingredient by ingredient Fennel

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?
  • 1 of the 1 matched ingredient can interact with medications — Fennel.
  • The most serious interaction on file is rated Moderate.
  • Some involve high-stakes drug classes: anticoagulant / antiplatelet drugs.
  • For scale: 741 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 taking this product, double-check with your pharmacist if you use anticoagulants or antiplatelets (blood thinners like warfarin or aspirin)—fennel may raise bleeding risk. Also check if you take contraceptives, hormone replacement therapy, medications processed by CYP3A4 enzymes, ciprofloxacin (Cipro), or tamoxifen (Nolvadex).

Check your own medication Run your meds through the checker above

The bottom line

Scorecard at a glanceFully disclosed formula with no established evidence rating for its marketed use. Moderate medication interactions have been identified, and safety information is well characterized.

This supplement is worth considering if you're looking into herbal support for painful periods and want to explore options with your doctor. If you take blood thinners, birth control, cancer medications, or most CYP3A4 substrates, you'll want to check with your pharmacist before starting.

Pregnant and breastfeeding individuals should talk it over with their healthcare provider first.

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

Assessment coverage: 1 of 1 active ingredient matched to our full ingredient reviews (monographs). Based on the product label dated Jul 25, 2016.

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 Fennel Seed 480 mg, straight from the product label.

Brand Nature's Way
Barcode (UPC) 033674127001
Net contents 100 Vegetarian Capsule(s)
Market status On market
Date entered into DSLD Jul 25, 2016
DSLD ID 63161
Product type Botanical
Supplement form Capsule
Dietary claims / uses All Other, Structure/Function
Intended target group(s) Vegetarian, Adult (18 - 50 Years), Gluten Free, Dairy Free, Sugar 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 Fennel Seed 480 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:
1 Capsule(s)
Maximum serving Sizes:
1 Capsule(s)
UPC/BARCODE
033674127001
IngredientAmount% DV
Fennel480 mg--

Other ingredients: plant-derived Capsule, Silica

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.
General Statements

Fennel (Foeniculum vulgare) helps sweeten breath and aids digestion. Our Fennel is carefully tested and produced to superior quality standards.

Premium Herbal

Precautions

Keep out of reach of children.

Safety sealed with printed outer shrinkwrap and inner seal. Do not use if either is broken or missing.

If pregnant, nursing or taking any medications, consult a healthcare professional before use.

Formulation

Gluten free. No sugar, salt, yeast, wheat, soy, corn, dairy products, artificial colors, flavors or preservatives.

VEGETARIAN

NON GMO

Seals/Symbols

VEGETARIAN

NON GMO Project VERIFIED nongmoproject.org

General

LN12700.B01 BLK8207B

FDA Disclaimer Statement

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

Suggested/Recommended/Usage/Directions

Recommendation: Take 1 capsule three times daily.

Brand IP Statement(s)

2015 Nature’s Way Brands, LLC

CERTIFIED AUTHENTIC TRU-ID

Health through the power of nature, that’s what it means to Trust the Leaf.

FDA Statement of Identity

Dietary Supplement

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

See for yourself

Fennel Seed 480 mg by Nature's Way label

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

Fennel Seed 480 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 Fennel Seed 480 mg by Nature's Way

This is the 1 active ingredient this product is made of. Select it to open its full monograph.

Serving size1 Capsule(s) Dosage formCapsule Amounts shown are per serving.

Fennel

Interacts with
740 drugs
480 mg per serving

Fennel is a Mediterranean herb widely used as a food and spice, and traditionally taken for digestive complaints, colic, and menstrual cramps. Some sm...

Fennel monograph & interactions

Other (inactive) ingredients: Plant-derived Capsule, Silica. These complete the product’s ingredient list but are not active constituents.

Interaction report

Fennel Seed 480 mg by Nature's Way Drug Interactions

Want to check YOUR meds against Fennel Seed 480 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
740Drugs
740 Moderate

Ingredients driving the most interactions

Fennel 740

Individual Drug Interactions

The ingredients in Fennel Seed 480 mg interact with 740 drugs. Click any drug to see the details.

1 of the 1 ingredient in Fennel Seed 480 mg interact with drugs. Each result below shows which ingredient is responsible. Fennel

Each ingredient & the kinds of drugs it affects

For each ingredient in Fennel Seed 480 mg with known interactions, here are the types of medications it can affect. Open any type for the detail — or search your exact drug in the checker above.

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
The maker

Brand information

Manufacturer and brand details for Fennel Seed 480 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

Fennel Seed 480 mg by Nature's Way: Common Questions

Does Fennel Seed 480 mg by Nature's Way interact with any medications?
Yes. Based on its ingredients, Fennel Seed 480 mg has a known interaction with 740 medications. Use the checker to see how it interacts with a specific drug.
How can one product interact with so many drugs?
Fennel Seed 480 mg contains a single active ingredient, and that one ingredient can interact with many different medications on its own. We check it against each medication and show the mechanism 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 fennel seed if I'm on birth control?
Fennel contains compounds with estrogenic activity that might theoretically reduce how well contraceptives work through competition for estrogen receptors. It's a moderate-severity interaction, so check with your pharmacist or doctor before adding this supplement to your routine.
What are the most common side effects?
Most people tolerate fennel well orally, but some experience gastrointestinal discomfort, increased sun sensitivity, or allergic reactions. Allergic reactions can occasionally be serious—watch for breathing trouble or palpitations and seek help right away if they occur.
Is fennel safe during pregnancy?
Concentrated fennel supplements are rated possibly unsafe in pregnancy due to limited safety data and hormone-like effects. Food amounts are probably fine, but medicinal doses should be avoided. Talk with your doctor before using this supplement if you're pregnant.
What is fennel actually used for?
Fennel seed is possibly effective for dysmenorrhea—painful menstrual periods. For other uses like anxiety, bronchitis, or bedwetting, we don't have reliable evidence yet to know if it works.
Can I use this if I take an antibiotic like Cipro?
Yes, but be aware: fennel may reduce how much ciprofloxacin your body absorbs and uses. Animal research shows fennel cuts ciprofloxacin levels nearly in half, likely because of minerals like calcium and iron in the seed. Check with your pharmacist before combining them.
Is there anything in this besides the fennel seed?
The capsule itself is plant-derived, and silica is added as an inactive ingredient. There are no other active ingredients—just fennel seed at 480 mg.

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

Not sure if Fennel Seed 480 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.

Fennel Seed 480 mg label
Go deeper

The Full Monographs Behind Fennel Seed 480 mg’s Ingredients

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

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 →
Sources

Sources & How We Checked

Fennel Seed 480 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 17 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.

Fennel 17 references
  1. Leung AY, Foster S. Encyclopedia of Common Natural Ingredients Used in Food, Drugs and Cosmetics. 2nd ed. New York, NY: John Wiley & Sons, 1996.
  2. Brinker F. Herb Contraindications and Drug Interactions. 2nd ed. Sandy, OR: Eclectic Medical Publications, 1998.
  3. Zhu M, Wong PY, Li RC. Effect of oral administration of fennel (Foeniculum vulgare) on ciprofloxacin absorption and disposition in the rat. J Pharm Pharmacol 1999;51:1391-6.
  4. Gral N, Beani JC, Bonnot D, et al. [Plasma levels of psoralens after celery ingestion]. Ann Dermatol Venereol 1993;120:599-603.
  5. Burkhard PR, Burkhardt K, Haenggeli CA, Landis T. Plant-induced seizures: reappearance of an old problem. J Neurol 1999;246:667-70. PubMed
  6. Rosti L, Nardini A, Bettinelli ME, Rosti D. Toxic effects of a herbal tea mixture in two newborns. Acta Paediatrica 1994;83:683. PubMed
  7. Cuzzolin L, Zaffani S, and Benoni G. Safety implications regarding use of phytomedicines. Eur.J Clin Pharmacol. 2006;62:37-42. PubMed
  8. Tognolini, M., Ballabeni, V., Bertoni, S., Bruni, R., Impicciatore, M., and Barocelli, E. Protective effect of Foeniculum vulgare essential oil and anethole in an experimental model of thrombosis. Pharmacol.Res 2007;56(3):254-260. PubMed
  9. Subehan, Usia, T., Iwata, H., Kadota, S., and Tezuka, Y. Mechanism-based inhibition of CYP3A4 and CYP2D6 by Indonesian medicinal plants. J Ethnopharmacol. 5-24-2006;105(3):449-455. PubMed
  10. Tognolini, M., Barocelli, E., Ballabeni, V., Bruni, R., Bianchi, A., Chiavarini, M., and Impicciatore, M. Comparative screening of plant essential oils: phenylpropanoid moiety as basic core for antiplatelet activity. Life Sci. 2-23-2006;78(13):1419-1432. PubMed
  11. Subehan, Zaidi, S. F., Kadota, S., and Tezuka, Y. Inhibition on human liver cytochrome P450 3A4 by constituents of fennel (Foeniculum vulgare): identification and characterization of a mechanism-based inactivator. J Agric.Food Chem. 12-12-2007;55(25):101 PubMed
  12. LEVY, S. B. Bronchial asthma due to ingestion of fennel and fennel seed. Ann.Allergy 1948;6(4):415.
  13. Ottolenghi, A., De Chiara, A., Arrigoni, S., Terracciano, L., and De Amici, M. [Diagnosis of food allergy caused by fruit and vegetables in children with atopic dermatitis]. Pediatr Med Chir 1995;17(6):525-530.
  14. Trabace L, Tucci P, Ciuffreda L, et al. "Natural" relief of pregnancy-related symptoms and neonatal outcomes: above all do no harm. J Ethnopharmacol. 2015;174:396-402. PubMed
  15. Denaxa D, Arkwright PD. Fennel as a cause of immediate hypersensitivity to toothpaste. Ann Allergy Asthma Immunol. 2020;125(1):99-100. PubMed
  16. Lee HW, Ang L, Lee MS, Alimoradi Z, Kim E. Fennel for reducing pain in primary dysmenorrhea: a systematic review and meta-analysis of randomized controlled trials. Nutrients 2020;12(11):3438. PubMed
  17. Mathew T, John SK, Javali M, Vasireddy M, Nadig R, Sarma GRK. Substance use related cluster headache: A case series. Headache 2022;62(7):908-910. PubMed

See these in context on the Fennel 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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