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Dietary supplement

Fennel Seed 550 mg Ingredients & Drug Interactions

by Dr. Clark Store

Fennel Seed 550 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 550 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 550 mg is a dietary supplement by Dr. Clark Store 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 ground Fennel. Use the checker below to test your specific medication, or read the full HelloPharmacist Interaction Report.

Jump to a section

Check Your Meds Against Fennel Seed 550 mg by Dr. Clark Store

Ask about any prescription or over-the-counter medication and we check it for interactions with Fennel Seed 550 mg by Dr. Clark Store — and tell you which ingredient is responsible.

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HelloPharmacist Scorecard of Fennel Seed 550 mg by Dr. Clark Store

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: ground fennel seed at 550 mg per capsule. Fennel is a traditional herbal remedy with constituents that have estrogenic activity.

The capsule itself is gelatin, 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: herbal digestive aid.
  • We looked for evidence on: Dyspepsia, Flatulence, Colic, Nausea and vomiting, Constipation, Irritable bowel syndrome (IBS) — and 2 related terms.
  • The closest evidence on file: Fennel is rated "Insufficient Reliable Evidence To Rate" for Constipation (Natural Medicines).
  • Also on file: Fennel is rated "Insufficient Reliable Evidence To Rate" for Dyspepsia, Flatulence, Irritable bowel syndrome (IBS), Nausea and vomiting, and more.

The evidence best supports fennel for dysmenorrhea (painful menstruation), where it's rated possibly effective. For bronchitis, anxiety, nocturnal enuresis (bedwetting), and cholera, we don't have enough reliable evidence to say whether it works.

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. The most common side effects are mild — gastrointestinal discomfort, photosensitivity (sun sensitivity), and allergic reactions in sensitive individuals.

Seizures have been reported rarely. Because this is a concentrated supplement rather than food amounts, the safety data advises against use during pregnancy and breastfeeding — the limited data and possible hormone-like effects raise concerns.

If you have a known fennel allergy or a history of bronchial asthma, talk with your pharmacist or doctor before taking it.

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.

Check your medications before taking this product if you use birth control or hormone replacement therapy, blood thinners (anticoagulants) or antiplatelet drugs, ciprofloxacin (Cipro), tamoxifen, or drugs metabolized by the CYP3A4 liver enzyme — all have moderate interactions documented with fennel.

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.

Fennel seed may help with period pain, but the moderate interactions with birth control, hormone therapy, blood thinners, and several other drug types make it important to check your medications first. The pregnancy and breastfeeding safety data suggests avoiding this supplement at medicinal doses in those situations.

Talk it over with your doctor or pharmacist before starting, especially if you take any prescription medications.

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 May 22, 2020.

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 550 mg, straight from the product label.

Brand Dr. Clark Store
Barcode (UPC) 652384103701
Net contents 100 Capsule(s)
Market status On market
Date entered into DSLD May 22, 2020
DSLD ID 219839
Product type Botanical
Supplement form Capsule
Dietary claims / uses All Other, Structure/Function
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 Fennel Seed 550 mg by Dr. Clark Store, 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)
Servings per container
100
UPC/BARCODE
652384103701
IngredientAmount% DV
ground Fennel550 mg--

Other ingredients: Gelatin 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: Adults and children 12 or more years of age, take 1 capsule daily, or as directed by a healthcare professional.

General Statements

Self Health Resource Center 1055 Bay Blvd., Ste A Chula Vista, CA 91911 Customer Service Toll Free: (866) DR-CLARK (372-5275) www.DrClarkStore.com

Leader in purity Established by Dr. Clark's family in 1993

Company does not adopt any Dr. Clark claims.

Formulation

Our products don't contain flow agents like magnesium stearate. Not now, not ever.

Herbal digestive aid

Seals/Symbols

Made in USA

FDA Statement of Identity

Dietary Supplement

Storage

Store at room temperature.

Precautions

Keep away from children.

Warning: If you are pregnant, nursing or taking any medications, consult your doctor before use.

If any adverse reactions occur, immediately stop using this product and consult your doctor. If seal under cap is damaged or missing, do not use.

FDA Disclaimer Statement

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

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

See for yourself

Fennel Seed 550 mg by Dr. Clark Store label

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

Fennel Seed 550 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 550 mg by Dr. Clark Store

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

Serving size1 Capsule(s) Dosage formCapsule Servings per container100 Amounts shown are per serving.

Ground Fennel

Interacts with
740 drugs
550 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...

Ground Fennel monograph & interactions

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

Interaction report

Fennel Seed 550 mg by Dr. Clark Store Drug Interactions

Want to check YOUR meds against Fennel Seed 550 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

ground Fennel 740

Individual Drug Interactions

The ingredients in Fennel Seed 550 mg interact with 740 drugs. Click any drug to see the details.

1 of the 1 ingredient in Fennel Seed 550 mg interact with drugs. Each result below shows which ingredient is responsible. ground Fennel

Each ingredient & the kinds of drugs it affects

For each ingredient in Fennel Seed 550 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.

ground 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
ground Fennel full monograph & interactions
The maker

Brand information

Manufacturer and brand details for Fennel Seed 550 mg, from the product label.

Dr. Clark Store

See all Dr. Clark Store products
Name
Dr. Clark Store
Street Address
1055 Bay Blvd., Ste A
City
Chula Vista
State
CA
ZipCode
91911
Phone Number
(866) 372-5275
Web Address
www.DrClarkStore.com
Pharmacist Counseling Corner

Fennel Seed 550 mg by Dr. Clark Store: Common Questions

Does Fennel Seed 550 mg by Dr. Clark Store interact with any medications?
Yes. Based on its ingredients, Fennel Seed 550 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 550 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.
Does fennel actually work for anything?
Fennel is possibly effective for dysmenorrhea — period pain. For other uses like bronchitis, anxiety, bedwetting, and cholera, we don't have enough reliable evidence to say whether it helps.
Can I take fennel if I'm pregnant or breastfeeding?
The safety data advises against medicinal or concentrated amounts during pregnancy and breastfeeding because there's limited data and fennel may have hormone-like effects. Food amounts are likely fine, but this supplement is a concentrated dose. Talk with your doctor or pharmacist for personalized advice.
What side effects might I get from fennel?
Most people tolerate it well. The common side effects are mild — stomach discomfort, sensitivity to sun, and allergic reactions in sensitive people. Seizures are rare. If you've had a fennel allergy or asthma triggered by fennel before, let your pharmacist know.
Can fennel interfere with my birth control?
Yes — fennel has estrogenic constituents that may compete with how birth control works, potentially lowering its effectiveness, especially at larger doses. Talk with your doctor or pharmacist about whether this is a concern for you.
I take a blood thinner. Is fennel safe?
Fennel may increase bleeding risk when combined with blood thinners or antiplatelet drugs. Check with your doctor or pharmacist before taking it — they'll know your full medication picture.

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

Not sure if Fennel Seed 550 mg is safe with your meds?

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Ask a pharmacist

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 550 mg label
Go deeper

The Full Monographs Behind Fennel Seed 550 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 550 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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