Last update Aug. 30, 2021


Likely Compatibility

Fairly safe. Mild or unlikely adverse effects. Compatible under certain circumstances. Follow-up recommended. Read Commentary.

The fruits of the plant are used. Contains essential oil (anethole 60-80%, estragole 5-10% and fenchone 7-15%), coumarins and flavonoids (, Dosoky 2021, Badgujar 2014, Raffo 2011, WHO 2010 p127-140, WHO 2007 p136- 149). Ascribed properties: expectorant, antiseptic, spasmolytic and carminative.

The essential oil components (trans-anethole, estragole and fenchone) are excreted in breast milk in small amounts (Denzer 2015, Hausner 2008).
Administration of a commercial infusion containing anise, coriander, fenugreek and fennel to nursing mothers did not produce adverse effects in their nursing children (Wagner 2019).
Excess maternal consumption (2 liters/day) of a mixed infusion of anise, galega, fennel and licorice caused lethargy, vomiting and hypotonia in two infants and their mothers (Rosti 1994).

Anethole, at high doses, is neurotoxic and convulsive (Bahr 2019, Skalli 2011, Burkhard 1999) and has weak mutagenic activity.
Fennel has estrogenic activity (Dosoky 2021, Amir 2011, Türkyilmaz 2008, EMA 2007, Javidnia 2003, Albert 1980) and has caused premature thelarche in young girls who were taking it for treatment of abdominal cramps (Türkyilmaz 2008).
Estragole has a carcinogenic effect in animals. In humans, at recommended doses, this effect has not been found.
It has not been possible to demonstrate a greater antioxidant capacity in the milk of women who took mixed infusions of this and other plants (Kavurt 2013).
Essential oils rich in anethole should not be consumed during lactation, pregnancy and if you have estrogen-dependent cancer (Dosoky 2021).

There is no credible evidence that it increases milk production (Sibeko 2021, Foong 2020, ABM 2018 and 2011, Sachs 2013, Mortel 2013). The administration of infusions of fennel or a mixture of herbs containing fennel to nursing mothers did not result in an increase in prolactin (Vafaei 2018, Özalkaya 2018), nor greater weight gain in infants (Özalkaya 2018), although greater production was noted of milk than in the control groups (Özalkaya 2018).
Reinforcing maternal self-confidence, assessing and correcting breastfeeding problems, and effectively supporting breastfeeding mothers are the best galactogogues (ABM 2018, Mannion 2012).

It is one of the most widely used plants in numerous cultures, including during pregnancy and lactation (Sibeko 2021, Kaygusuz 2021, Sibeko 2021, Badgujar 2014, Sim 2013, Zaffani 2006).
Fennel has been used to treat infant colic (Harb 2018, Gordon 2018, Bruyas 2012, Abdulrazzaq 2009, Savino 2005) and as a galactogogue (Sim 2013, Muresan 2011, Ayers 2000) and there have been very few reported side effects (Gordon 2018).

The moderate consumption in quantity and duration of fennel infusions would be compatible with breastfeeding.

Culinary consumption as a food or aromatic condiment is safe.

Precautions when taking plant preparations:
1. Make sure they are from a reliable source: poisonings have occurred due to confusion of one plant with another with toxic properties, poisonings due to containing heavy metals extracted from the soil, and food poisoning due to contamination with bacteria or fungi (Anderson 2017).
2. Do not take in excess; follow the recommendations of expert phytotherapy professionals. “Natural” products are not good in any quantity: plants contain active substances from which much of our traditional pharmacopoeia has been obtained and can cause poisoning or act as endocrine disruptors (contain phytoestrogens: Powers 2015) if consumed in quantity or for an exaggerated time.

Suggestions made at e-lactancia are done by APILAM team of health professionals, and are based on updated scientific publications. It is not intended to replace the relationship you have with your doctor but to compound it. The pharmaceutical industry contraindicates breastfeeding, mistakenly and without scientific reasons, in most of the drug data sheets.

Jose Maria Paricio, Founder & President of APILAM/e-Lactancia

Your contribution is essential for this service to continue to exist. We need the generosity of people like you who believe in the benefits of breastfeeding.

Thank you for helping to protect and promote breastfeeding.

José María Paricio, founder of e-lactancia.

Other names

Fennel is also known as

Fennel in other languages or writings:


Main tradenames from several countries containing Fennel in its composition:


Variable Value Unit
Theoretical Dose anetol: 0.0035 mg/Kg/d


  1. Vanaclocha B, Cañigueral S. 1992 - - Disponible en: Consulted on Dec. 21, 2023 Abstract
  2. Dosoky NS, Setzer WN. Maternal Reproductive Toxicity of Some Essential Oils and Their Constituents. Int J Mol Sci. 2021 Feb 27;22(5). pii: 2380. Abstract
  3. Sibeko L, Johns T. Global survey of medicinal plants during lactation and postpartum recovery: Evolutionary perspectives and contemporary health implications. J Ethnopharmacol. 2021 Apr 24;270:113812. Abstract
  4. Kaygusuz M, Gümüştakım RŞ, Kuş C, İpek S, Tok A. TCM use in pregnant women and nursing mothers: A study from Turkey. Complement Ther Clin Pract. 2021 Feb;42:101300. Abstract
  5. Foong SC, Tan ML, Foong WC, Marasco LA, Ho JJ, Ong JH. Oral galactagogues (natural therapies or drugs) for increasing breast milk production in mothers of non-hospitalised term infants. Cochrane Database Syst Rev. 2020 May 18;5:CD011505. Abstract Full text (link to original source)
  6. Wagner CL, Boan AD, Marzolf A, Finch CW, Morella K, Guille C, Gardner Z, Marriott BP. The Safety of Mother's Milk® Tea: Results of a Randomized Double-Blind, Controlled Study in Fully Breastfeeding Mothers and Their Infants. J Hum Lact. 2019 May;35(2):248-260. Abstract
  7. Bahr TA, Rodriguez D, Beaumont C, Allred K. The Effects of Various Essential Oils on Epilepsy and Acute Seizure: A Systematic Review. Evid Based Complement Alternat Med. 2019 May 22;2019:6216745. Abstract
  8. Gordon M, Biagioli E, Sorrenti M, Lingua C, Moja L, Banks SS, Ceratto S, Savino F. Dietary modifications for infantile colic. Cochrane Database Syst Rev. 2018 Oct 10;10:CD011029. Abstract
  9. ABM: Brodribb W. ABM Clinical Protocol #9: Use of Galactogogues in Initiating or Augmenting Maternal Milk Production, Second Revision 2018. Breastfeed Med. 2018 Jun;13(5):307-314 Abstract Full text (link to original source) Full text (in our servers)
  10. Özalkaya E, Aslandoğdu Z, Özkoral A, Topcuoğlu S, Karatekin G. Effect of a galactagogue herbal tea on breast milk production and prolactin secretion by mothers of preterm babies. Niger J Clin Pract. 2018 Jan;21(1):38-42. Abstract Full text (link to original source) Full text (in our servers)
  11. Vafaei F, Valizadeh S, Javadzadeh Y, Jafarabadi MA. The effect of fennel syrup on prolactin levels of blood serum in newly delivered mothers: A triple-blind randomized controlled trial. Ann Trop Med Public Health. 2018;16(Sp Iss):S44389. Abstract Full text (link to original source)
  12. Anderson PO. Herbal Use During Breastfeeding. Breastfeed Med. 2017 Abstract
  13. Harb T, Matsuyama M, David M, Hill RJ. Infant Colic-What works: A Systematic Review of Interventions for Breast-fed Infants. J Pediatr Gastroenterol Nutr. 2016 May;62(5):668-86. Abstract
  14. Denzer MY, Kirsch F, Buettner A. Are odorant constituents of herbal tea transferred into human milk? J Agric Food Chem. 2015 Jan 14;63(1):104-11. Abstract
  15. Powers CN, Setzer WN. A molecular docking study of phytochemical estrogen mimics from dietary herbal supplements. In Silico Pharmacol. 2015 Mar 22;3:4. Abstract Full text (link to original source) Full text (in our servers)
  16. Badgujar SB, Patel VV, Bandivdekar AH. Foeniculum vulgare Mill: a review of its botany, phytochemistry, pharmacology, contemporary application, and toxicology. Biomed Res Int. 2014;2014:842674. Abstract
  17. Kavurt S, Bas AY, Aydemir O, Yucel H, Isikoglu S, Demirel N. The effect of galactagogue herbal tea on oxidant and anti-oxidant status of human milk. J Matern Fetal Neonatal Med. 2013 Abstract
  18. Sachs HC; Committee On Drugs. The transfer of drugs and therapeutics into human breast milk: an update on selected topics. Pediatrics. 2013 Sep;132(3):e796-809. Abstract Full text (link to original source) Full text (in our servers)
  19. Mortel M, Mehta SD. Systematic review of the efficacy of herbal galactogogues. J Hum Lact. 2013 May;29(2):154-62. Abstract
  20. Sim TF, Sherriff J, Hattingh HL, Parsons R, Tee LB. The use of herbal medicines during breastfeeding: a population-based survey in Western Australia. BMC Complement Altern Med. 2013 Abstract Full text (link to original source) Full text (in our servers)
  21. Mannion C, Mansell D. Breastfeeding self-efficacy and the use of prescription medication: a pilot study. Obstet Gynecol Int. 2012;2012:562704. Abstract Full text (link to original source) Full text (in our servers)
  22. Bruyas-Bertholon V, Lachaux A, Dubois JP, Fourneret P, Letrilliart L. [Which treatments for infantile colics?]. Presse Med. 2012 Abstract
  23. Raffo A, Nicoli S, Leclercq C. Quantification of estragole in fennel herbal teas: implications on the assessment of dietary exposure to estragole. Food Chem Toxicol. 2011 Abstract
  24. ABM. Comité de Protocolos de la Academia Médica de Lactancia Materna. ABM Protocolo Clínico #9: Uso de Galactogogos para Iniciar o aumentar la tasa de secreción de Leche Materna. Breastfeed Med. 2011 Full text (link to original source) Full text (in our servers)
  25. Amir LH, Pirotta MV, Raval M. Breastfeeding--evidence based guidelines for the use of medicines. Aust Fam Physician. 2011 Sep;40(9):684-90. Review. Abstract Full text (link to original source) Full text (in our servers)
  26. Muresan M. Successful relactation--a case history. Breastfeed Med. 2011 Abstract
  27. ABM. Academy Of Breastfeeding Medicine Protocol Committee. ABM Clinical Protocol #9: Use of galactogogues in initiating or augmenting the rate of maternal milk secretion (First Revision January 2011). Breastfeed Med. 2011 Abstract Full text (link to original source) Full text (in our servers)
  28. Skalli S, Soulaymani Bencheikh R. Epileptic seizure induced by fennel essential oil. Epileptic Disord. 2011 Sep;13(3):345-7. Abstract
  29. WHO. World Health Organization. WHO monographs on medicinal plants commonly used in the Newly Independent States (NIS). WHO monographs. 2010 Full text (in our servers)
  30. Abdulrazzaq YM, Al Kendi A, Nagelkerke N. Soothing methods used to calm a baby in an Arab country. Acta Paediatr. 2009 Abstract
  31. Türkyilmaz Z, Karabulut R, Sönmez K, Can Başaklar A. A striking and frequent cause of premature thelarche in children: Foeniculum vulgare. J Pediatr Surg. 2008 Nov;43(11):2109-11. Abstract
  32. Hausner H, Bredie WL, Mølgaard C, Petersen MA, Møller P. Differential transfer of dietary flavour compounds into human breast milk. Physiol Behav. 2008 Sep 3;95(1-2):118-24. Abstract
  33. European Medicines Agency (EMeA) COMMUNITY HERBAL MONOGRAPH ON FOENICULUM VULGARE MILLER SUBSP. VULGARE VAR. VULGARE, AETHEROLEUM. COMMUNITY HERBAL MONOGRAPH. 2007 Full text (link to original source) Full text (in our servers)
  34. WHO. World Health Organization. Geneva. WHO monographs on selected medicinal plants. Volume 3. WHO monographs. 2007 Full text (link to original source) Full text (in our servers)
  35. Zaffani S, Cuzzolin L, Benoni G. Herbal products: behaviors and beliefs among Italian women. Pharmacoepidemiol Drug Saf. 2006 Abstract
  36. Savino F, Cresi F, Castagno E, Silvestro L, Oggero R. A randomized double-blind placebo-controlled trial of a standardized extract of Matricariae recutita, Foeniculum vulgare and Melissa officinalis (ColiMil) in the treatment of breastfed colicky infants. Phytother Res. 2005 Abstract
  37. Javidnia K, Dastgheib L, Mohammadi Samani S, Nasiri A. Antihirsutism activity of Fennel (fruits of Foeniculum vulgare) extract. A double-blind placebo controlled study. Phytomedicine. 2003 Abstract
  38. Ayers JF. The use of alternative therapies in the support of breastfeeding. J Hum Lact. 2000 Abstract
  39. Burkhard PR, Burkhardt K, Haenggeli CA, Landis T. Plant-induced seizures: reappearance of an old problem. J Neurol. 1999 Aug;246(8):667-70. Abstract
  40. Rosti L, Nardini A, Bettinelli ME, Rosti D. Toxic effects of a herbal tea mixture in two newborns. Acta Paediatr. 1994 Jun;83(6):683. No abstract available. Abstract
  41. Albert-Puleo M. Fennel and anise as estrogenic agents. J Ethnopharmacol. 1980 Abstract

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