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Onion (Allium Cepa)


Onions health benefits are due to its potent anti-oxidant, immuno-modulatory and anti-inflammatory. These three medicinal properties help to fight against a variety of diseases in which onions are used for therapeutic purposes.

Onions as food provide a good amount of nutrients to the body, which further enhances its importance. It boosts immunity and prevents diseases. In some Asian countries, it is a crucial part of almost every recipe. Onion is a good nutritious vegetable, which we can use on regular basis and include in our daily diet.

Onions as medicine help treating high cholesterol, diabetes, joint disorders, digestive ailments, loss of appetite, gallbladder diseases, angina pectoris, high blood pressure, atherosclerosis, sore throat, asthma, bronchitis, cough, intestinal gas and intestinal worms.

Botanical Description

Basic Information

Scientific Name ALLIUM CEPA
English Name ONION

Botanical Classification (Taxonomy)

Super Division EMBRYOPHYTA

Plant Description

Type of Plant Biennial plant
Native Range (Geographic Distribution) South West Asia
Height (grows up to) 70 cm
Habitat (type of environment) Onions can grow in both warm and cold climates
Soil All types of oil vary from dry to moist and mineral based soils.
Parts used Shoots and Bulbs
Roots Small and shallow roots
Stem Erect and stiff stem
Flowers White to Pink flowers on the top of stem
Seeds Black and small

Medicinal Parts

  1. Shoots
  2. Bulbs
  3. Onion Seeds

Phytochemistry (Active Constituents)

Onions contain following phytochemicals.

  1. Kaempferol
  2. Myricetin
  3. Quercetin
  4. Quercitrin
  5. Allyl sulfide

Onions contain organosulfur compounds. These compounds give a unique smell and taste to onions. The main active constituent in onions is QUERCETIN, which is one of flavonoid that exhibits a good antioxidant property. Another phytochemical is Allyl sulfide. It also possesses for antioxidant and anti-inflammatory properties.

Medicinal Properties

Onion (ALLIUM CEPA) has following healing properties.

  1. Antioxidants
  2. Anti-inflammatory
  3. Anti-cholesterol
  4. Anti-hypertensive
  5. Anti-cancer
  6. Anti-arthritic
  7. Anti-bacterial or Anti-biotic
  8. Bronchodilator
  9. Expectorant
  10. Anti-spasmodic
  11. Antiseptic
  12. Carminative
  13. Anti-coagulant
  14. Fibrinolytic
  15. Anthelmintic

Therapeutic Indications

Onions (ALLIUM CEPA) are helpful in following health conditions.

  1. Scar removal
  2. Burns and wounds
  3. Hair loss
  4. Diabetes
  5. Atherosclerosis
  6. High cholesterol
  7. High blood pressure
  8. Asthma
  9. Upset stomach
  10. Loss of appetite
  11. Common clod
  12. Whooping cough
  13. Sore throat
  14. Bronchitis

Health Benefits & Medicinal Uses

Onions are rich in potassium, fiber, sulfur, Vitamin C, Vitamin B. They are low in fat, sodium and cholesterol. Due to their medicinal properties, onions can help curing common cold, fever, sore throat, cough, allergies and many more. Some of important health benefits and medicinal uses of onions are described underneath.

Preventing infections

Onions have antiseptic, anti-biotic, carminative and antimicrobial properties, which help in staying away from different kinds of infections. Onions active constituents inhibit bacterial growth and are effective against both types of bacteria gram positive and gram negative. (1, 2, 3)

Common Cold & Cough

A mixture of onion juice along with honey can help in common cold. You can also add a pinch of black pepper in the mixture for instant results stopping nasal discharge. This mixture also helps curing cough. (4, 5)

Bronchitis & Asthma

Onions have mild anti-asthmatic and potent anti-inflammatory effects. However, onions cannot be used for therapeutic purposes in bronchitis and asthma, but it can be a good diet for patients with bronchitis and asthma. (6, 7, 8)

For asthma, a mixture of onion juice, honey and black pepper is useful. It reduces chest congestion, wheezing and gives relief from breathing difficulty.

High blood pressure

Onion has mild anti-hypertensive property. It can help in reducing and managing the elevated blood pressure. However, its effect is not so potent that can alone help reducing blood pressure, but it is a good diet for people with hypertensive heart diseases. The active compound QUERCETIN is responsible for anti-hypertensive property of onions. (9, 10, 11)

High cholesterol & Atherosclerosis

Some studies suggest that onion prevents atherosclerosis (hardening of blood vessels) and reduces serum cholesterol. Raw and processed onions both are beneficial for inhibition of atherosclerosis and reduction of elevated lipids. (12, 13, 14, 15, 16, 17)

Prevents heart attacks

Onions are good for patients prone to heart attack or other heart diseases. Onions exhibit fibrinolytic and anti-coagulant characteristics, which help preventing clot formation in the coronary arteries of the heart. (18, 19)

Hair loss (alopecia areata)

Onion juice tropical application can help reducing hair loss and increasing re-growth of hairs on the scalp. Onion juice improves the blood circulation to the hair roots and scalp. Sulfur present in onion juice helps in production of collagen tissues. Collagen formation is necessary for the hair growth. Onion juice is also anti-dandruff and anti-microbial, which helps reducing scalp infections and provides strength to the hairs. It further prevents hair thinning. (20, 21)

Eyesight & Cataract

Onion juice and honey mixture is used for instillation in eyes for improving eyesight and preventing formation of cataract. (22)

In India, many people are using this mixture for stopping progress of cataract and delaying eye operation for it, but it lacks scientific evidences.

Ayurveda recommends using onion juice and honey eye drops for blaring vision, reduced eyesight, eye infections, eye occlusions, chalazion, eye floaters and hazy vision.

Loss of appetite & Indigestion

Onion can help your digestive system due to release of the digestive juices and curing loss of appetite. Onion is digestive stimulant and stimulates the production of gastric juice and bile salts, which helps in improving appetite and curing indigestion.


However, evidences on effects on onions in sleeping disorders are not sufficient, but some people believe better sleep after including onions in their diet.

For sleeplessness, drinking 4 teaspoons of raw onion juice before bedtime helps inducing good sleep. Fried onions can also help reducing restlessness and sleeplessness.

Recurring hiccups

Eating onion slices with salt after meal helps reducing recurring hiccups. For a complete cure, you should eat onion salted slices for a week.

Intestinal parasites/worms

Onion has anthelmintic property. Its juice is used for expelling and destroying intestinal parasites. Taking one teaspoon of onion juice after every two hours helps expelling intestinal worms.


Raw Onion 3 grams to 20 grams
Onion Juice 1 tsp. to 4 tsp.
Onion Extract 125 mg to 500 mg

The appropriate dosage can be different according to age, health conditions and several other factors.  Therefore, consult an herbalist and alternative health professional for the appropriate therapeutic dosage according to your health condition and symptoms.

Caution & Side Effects

Onions are POSSIBLY SAFE in food and therapeutic amounts.

Pregnancy & Breastfeeding

Onions use in pregnancy and breastfeeding is LIKELY SAFE, but you should avoid using it in larger amounts.


Acid reflux & Heartburn

However, onions do not cause acid reflux or heartburn in healthy people, but it is not good food for people suffering with acid reflux, heartburn and gastroesophageal reflux (GERD). Onions can aggravate the symptoms in people with these diseases. (23)

Bleeding disorders

Onions exhibit anti-coagulant and fibrinolytic properties, which can be harmful for people with bleeding disorders. (24, 25)

Drug Interactions

  1. Aspirin can increase sensitivity to onions and results hypersensitivity reaction.
  2. Lithium can interact with onion.
  3. Anti-diabetic drugs can also interact with onions resulting in decrease in blood sugar and hypoglycemia. However, it is a rare effect, but you should monitor blood sugar level regularly while using onions.
  4. Consult your doctor if you are eating onions and taking Anticoagulant and Anti-platelet drugs. Onions are also Anticoagulant, so they can increase the clotting time. It might result in bruising and bleeding.
  5. Avoid using onions before and after surgery.

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