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Dietary supplement

Fennel 2,000 mg Ingredients & Drug Interactions

by Nature's Answer

Fennel 2,000 mg label
See full label image
Liquid Category: Botanical
Most serious interaction: Moderate
Clinical methodology reviewed by · Updated Sep 9, 2026 · Label data from the NIH DSLD
What is this page for?

First and foremost: checking Fennel 2,000 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 2,000 mg is a dietary supplement by Nature's Answer 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 (Foeniculum vulgare) seed extract. 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 2,000 mg by Nature's Answer

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HelloPharmacist Scorecard of Fennel 2,000 mg by Nature's Answer

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 (Foeniculum vulgare) seed extract in a 2,000 mg dose per serving. Fennel seed has been used traditionally to support digestive comfort and other wellness goals.

The extract is delivered in a liquid form with purified water, vegetable glycerin, and a small amount of certified organic alcohol as inactive ingredients.

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 Fennel's overall clinical evidence instead.

Moderate

Some clinical evidence supports Fennel 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 ingredient's overall clinical evidence instead.
  • On file: Dysmenorrhea — rated "Possibly Effective" (Natural Medicines).

Fennel is possibly effective for dysmenorrhea (painful periods). For other uses including bronchitis, anxiety, bedwetting (nocturnal enuresis), and cholera, the evidence in our data is insufficient to establish whether fennel works.

If you're considering this product for a specific condition, 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 used as food, but concentrated supplements like this one require more caution. The most common side effects reported are gastrointestinal discomfort, sensitivity to sunlight (photosensitivity), and allergic reactions in sensitive individuals.

Rarely, seizures have been reported. Some people have experienced allergic reactions to fennel itself—reactions that resolved quickly but included breathing difficulty and wheezing.

Fennel has also been associated with bronchial asthma in some cases. The safety data advises against using medicinal or concentrated amounts of fennel during pregnancy due to limited safety information and fennel's hormone-like effects.

For breastfeeding, food amounts are likely fine, but medicinal doses and fennel essential oil have not been well studied, so talk with your doctor or pharmacist before use.

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, check with your doctor or pharmacist if you take blood thinners (anticoagulants or antiplatelet drugs), contraceptive medications, hormone replacement therapy, ciprofloxacin (Cipro) or similar antibiotics, tamoxifen (Nolvadex), or any drugs metabolized by your liver's CYP3A4 enzyme. Fennel may reduce the effectiveness of some of these or increase your bleeding risk with others.

Check your own medication Run your meds through the checker above

The bottom line

Scorecard at a glanceFully disclosed formula with some supporting evidence behind its ingredients' uses. Moderate medication interactions have been identified, and safety information is well characterized.

Fennel may help with painful periods, but it has multiple documented interactions with blood thinners, contraceptives, hormone replacement therapy, certain antibiotics, and cancer medications—all rated Moderate severity. If you take any prescription medications, especially those for blood clotting or cancer, check them against the medication tool on this page before starting.

Pregnant and breastfeeding people should talk with their doctor or pharmacist first. Your own healthcare provider can help you weigh whether fennel is right for you.

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, 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 2,000 mg, straight from the product label.

Brand Nature's Answer
Barcode (UPC) 083000002892
Net contents 1 fl. Oz.; 30 mL
Market status On market
Date entered into DSLD May 22, 2016
DSLD ID 60067
Product type Botanical
Supplement form Liquid
Dietary claims / uses All Other, Structure/Function
Intended target group(s) Adult (18 - 50 Years), Kosher, 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 Fennel 2,000 mg by Nature's Answer, 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 mL
Maximum serving Sizes:
2 mL
Servings per container
15
UPC/BARCODE
083000002892
IngredientAmount% DV
Fennel (Foeniculum vulgare) seed extract2000 mg--

Other ingredients: purified Water, Vegetable Glycerin, 12-15% certified organic Alcohol

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 Disclaimer Statement

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

Seals/Symbols

Gluten Free

K Parve

Bio-Chelated Cold Extraction Process

Formula

K Parve

Foeniculum vulgare

Low Alcohol

General

9237 Rev. 815 1061

General Statements

Since 1972

Super Concentrated 2,000 mg

Our facility is cGMP certified, organic and kosher certified.

Brand IP Statement(s)

Advanced Botanical Fingerprint

Discover Nature's Answer

Our organic alcohol extracts are produced using our cold Bio-Chelated proprietary extraction process, yielding a Holistically Balanced Advanced Botanical Fingerprint extract in the same synergistic ratios as in the plant.

2015 Nature's Answer

Formulation

Gluten-Free

FDA Statement of Identity

Herbal Supplement

Suggested/Recommended/Usage/Directions

Suggested Use: As a dietary supplement, take 1-2 mL (28-56 drops) three (3) times a day in a small amount of water. Shake well.

Precautions

Keep out of reach of children.

Warning: Do not use if pregnant or nursing.

Do not use if safety seal is damaged or missing.

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

See for yourself

Fennel 2,000 mg by Nature's Answer label

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

Fennel 2,000 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 2,000 mg by Nature's Answer

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

Serving size1 mL Dosage formLiquid Servings per container15 Amounts shown are per serving.

Fennel (Foeniculum vulgare) seed extract

Interacts with
740 drugs
2000 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 (Foeniculum vulgare) seed extract monograph & interactions

Other (inactive) ingredients: Purified Water, Vegetable Glycerin, 12-15% certified organic Alcohol. These complete the product’s ingredient list but are not active constituents.

Interaction report

Fennel 2,000 mg by Nature's Answer Drug Interactions

Want to check YOUR meds against Fennel 2,000 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 (Foeniculum vulgare) seed extract 740

Individual Drug Interactions

The ingredients in Fennel 2,000 mg interact with 740 drugs. Click any drug to see the details.

1 of the 1 ingredient in Fennel 2,000 mg interact with drugs. Each result below shows which ingredient is responsible. Fennel (Foeniculum vulgare) seed extract

Each ingredient & the kinds of drugs it affects

For each ingredient in Fennel 2,000 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.

Fennel (Foeniculum vulgare) seed extract6 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 (Foeniculum vulgare) seed extract full monograph & interactions
The maker

Brand information

Manufacturer and brand details for Fennel 2,000 mg, from the product label.

Nature's Answer

See all Nature's Answer products
Name
Nature's Answer
City
Hauppauge
State
NY
ZipCode
11788-3943
Phone Number
(800) 439-2324
Web Address
www.naturesanswer.com
Pharmacist Counseling Corner

Fennel 2,000 mg by Nature's Answer: Common Questions

Does Fennel 2,000 mg by Nature's Answer interact with any medications?
Yes. Based on its ingredients, Fennel 2,000 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 2,000 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.
What is fennel seed extract used for?
Fennel has been traditionally used to support digestive comfort and other wellness purposes. Our data shows it's possibly effective for painful periods (dysmenorrhea). For other uses like bronchitis or anxiety, the evidence we hold is insufficient to establish whether it works.
Can I take fennel if I'm on birth control?
Fennel contains compounds with estrogenic activity that might theoretically decrease birth control effectiveness. Before starting this product while taking contraceptives, talk with your doctor or pharmacist to confirm it's safe for you.
Can I take fennel if I'm pregnant or breastfeeding?
The safety data advises against medicinal or concentrated amounts of fennel during pregnancy due to limited safety information and fennel's hormone-like effects. For breastfeeding, food amounts are likely fine, but medicinal doses are not well studied. Talk with your doctor or pharmacist before use.
What are the most common side effects of fennel?
Most people tolerate fennel well, but gastrointestinal discomfort, sensitivity to sunlight, and allergic reactions can occur in some individuals. Rarely, seizures have been reported. If you have a known fennel allergy, avoid this product.
Can fennel interact with blood thinners?
Yes. Animal research suggests fennel has antiplatelet effects that might increase bleeding risk when combined with blood thinners (anticoagulants or antiplatelet drugs). This interaction is rated Moderate severity, so check with your doctor or pharmacist before combining them.
Can fennel reduce the effectiveness of my antibiotic?
Possibly. Animal research shows fennel may reduce ciprofloxacin (Cipro) levels by nearly half, possibly because minerals in fennel bind to the antibiotic. If you take ciprofloxacin or similar antibiotics, talk with your doctor or pharmacist before starting fennel.

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

Not sure if Fennel 2,000 mg is safe with your meds?

Our pharmacists answer your medication & supplement questions — free.

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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 2,000 mg label
Go deeper

The Full Monographs Behind Fennel 2,000 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 2,000 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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