Fennel Essential Oil Health Benefits and Side Effects

Fennel essential oil benefits


Fennel essential oil is extracted by steam distillation. On the fresh herbage whole plant and distilled at the flowering stage or from fennel seed (fruits) (1). Fennel essential oil benefits are controlled appetite antimicrobial, muscle relaxing, and insecticidal properties.

The scientific name is Foeniculum vulgare Mill., family Apiaceae (Umbelliferae) is an annual, biennial, or perennial aromatic herb and found in two types

  1. Sweet fennel (F. vulgare Miller var. dulce)
  2. Bitter fennel (F. vulgare Miller var. vulgare)

Use of Fennel essential oil

Fennel essential oil has a characteristic pleasant spicy aroma that makes it an excellent aromatic ingredient in baked goods, meat and fish dishes, ice cream, and alcoholic beverages. Not only this the fennel essential oil benefits aromatherapy also. This oil is also used in pharmaceutical cosmetic, and perfume industry applications.

Geographical distribution

Fennel essential oil is native to southern Europe and the Mediterranean area such as Bulgaria, France, Germany, Italy, Romania, Hungary, Turkey, Ukraine, Russia, Yugoslavia, India, China, Argentina, and the United States.

Common name

Fennel, Razianaj, Razianeh, Badiyan, Marsoun, Arpabodiyon

Constituents of Fennel essential oil

Fennel fruit contains essential oil mainly composed of trans-anethole, fenchone, carvone, and estragole. The ratios of essential oil from sweet and bitter fennels were found similar (average 3.00%). The presence of trans-anethole and fenchone in varying quantities is responsible for a different taste of sweet and bitter fennel essential oil (2).


Sweet fennel

Bitter fennel

Oil content (%) 12.22 14.41
Fenchone 0.62% 5.03%
Trans-anethole 84–95% 61–75%
p-Anisaldehyde 0.24
estragole 2.87% 15.51%
Limonene 0.91 1.08
α-Pinene 0.57
y-Terpinene 0.84

Fennel essential oil benefits

Fennel essential oil health benefits

Fennel essential oil has benefits like antimicrobial, anticancer, muscle relaxing, digestive, diuretic, and treating respiratory and gastrointestinal disorders. 

1. Possible hepatoprotective activities of Fennel essential oil

Furthermore, d-limonene and β-myrcene found in fennel essential oil (0.4 ml/kg) prevents lipid peroxidation and scavenge harmful free radicals thus this oil shows possible hepatoprotective activities and prevents liver cell damage induced by CCl4 toxicity (3).

2. May treat infantile colic and irritable bowel syndrome

Curcumin and fennel essential oil (42 mg and 25 mg) for 30 days is helpful for the relief of gastrointestinal symptoms and reduces abdominal pain intensity and other bowel symptoms. This oil has antispasmodic and carminative effects which makes it safe, well-tolerated, and induces symptom relief in patients with IBS (4). Fennel essential oil is also useful for reducing intestinal spasms and increasing motility of the small intestine thus decreasing the intensity of infantile (5).

3. Possible mosquito repellent

Fennel essential oil-containing products (5% aerosol and 8% cream) have good larvicidal activity against Anopheles, Aedes, and Armigeres with reductions in growth (84% and 70 %) at 90 min after exposure than any other cream.

Thus this oil may be used to protect humans and domestic animals from vector-borne diseases and nuisance caused by mosquitoes (6).

4. Antimicrobial properties of Fennel essential oil

An antimicrobial compound is known as trans-anethole which fights against various microbes such as Staphylococcus aureus, Candida albicans, Alternaria alternate, Aspergillus species and dermatophytes, Bacillus cereus, Bacillus megaterium, Bacillus pumilus, Bacillus subtilis, Escherichia coli, Klebsiella pneumonia, Micrococcus luteus, Pseudomonas putida, and Pseudomonas syringae.

Thus this oil is effective against most of the foodborne pathogenic, saprophytic, probiotic, and mycotoxigenic microorganisms tested (7,8).

5. Insecticidal properties of Fennel essential oil

It contains a good amount of fenchone and p-anisaldehyde which show insecticide effects against house dust mites such as Dermatophagoides farinae and Dermatophagoides pteronyssinus. Moreover, this oil is also rich in carvone which shows wonderful acaricidal activity against Tyrophagus putrescentiae (stored food mites) (10).

6. Muscle relaxing properties of Fennel essential oil during Menstrual pain

Fennel essential oil (100 mg/ml) possesses nerve and muscle relaxing effects due to the presence of anol or dimethylated anethole that may have mild estrogen-like activity inhibit spasms or contraction in smooth muscle and relieve dysmenorrheal (11).

7. Effect of Fennel essential oil on women’s health

Fennel essential oil has a wonderful effect on the treatment of dysmenorrhea, premenstrual syndrome, amenorrhea, menopause, lactation, and polycystic ovary syndrome.

Other fennel essential oil benefits are good for skin and hair and improve breastfeeding.

20 to 30 drops of fennel essential oil are beneficial to reduce the severity of anxiety, depression, and premenstrual syndrome. Thus this oil exhibits estrogenic activity promotes menstruation alleviates the symptoms of female climacteric, and increases libido (12).

8. Possible antiplatelet and antithrombotic properties of Fennel essential oil

30 mg/kg of fennel essential oil for 5 days is helpful to stop the formation of blood clots and vasorelaxant action thus preventing paralysis. Furthermore, the intake of this oil (100 mg/kg) also protects from the gastric lesion, therefore, it contains gastroprotective effects (13).

9. May possess anthelmintic properties

100 mg/ml of fennel essential oil possesses anthelmintic effects that kill Schistosoma mansoni worms (50% of both male and female), their eggs, decrease their motor activity and separate all the coupled pairs of worms due to the presence of anethole and limonene obtained from this oil (14).

10. Fennel essential oil controls the Appetite

Around 2-4 drops or 0.1-0.2 ml of fennel essential oil inhaled two times a day for 10 minutes for 8 weeks on dried cloth or cotton ball helps in controlling the appetite. As it contains trans-anethole which reduces appetite (15).

This oil (100 mg /kg) for 4 weeks also decreases in percentual feed intake by 50 % in pigs (16). Thus this oil is classified as an Appetite controller not as an ‘appetite promoter’ by lowering the food efficiency rate rather than the feed intake in diets for both humans and animals (17).

12. Possible nematicidal properties of Fennel essential oil

About 200 and 150 mg/kg of fennel essential oil immobilize more than 80% of juveniles of the root-knot nematode Meloidogyne javanica at a concentration of 1000 μL/liter and inhibit nematode hatching (18).

Side effect of Fennel essential oil

Risk of epileptic seizures

Accidentally consumption of fennel essential oil by women causes tonic-clonic seizures and remain unconscious for 45 minutes because this oil is rapidly absorbed and demonstrates primary neurotoxicity.

Therefore, a person who is suffering from epilepsy or a history of epilepsy is at high risk and should avoid such oil (19).


The accepted dosage for essential oil is 2 to 5 drops diluted with water after each meal for a healthy person.

Super summary

Fennel essential oil controls appetite when inhaled. The oil has antimicrobial, muscle-relaxing, and insecticidal properties. This oil also shows a wonderful effect on the treatment of dysmenorrhea, premenstrual syndrome, amenorrhea, menopause, lactation, and polycystic ovary syndrome.

Edited By: Dr.Asha Jyoti Bharati

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