Kitchen onion

Author: Prof. Dr. med. Peter Altmeyer

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Last updated on: 18.07.2021

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Allii cepae bulbi; allium cepa; Allium cepa L.; onion; Onion

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The kitchen onion (Allium cepa) belongs to the lily family and is one of the oldest cultivated plants of mankind (it has been cultivated as a medicinal, spice and vegetable plant for more than 5000 years). In Central Europe, the onion has only been known since the Middle Ages.

Kitchen onion is the parent plant of Allii cepae bulbi the drug monographed by Commission E and WHO (Ammon HPT 2014).

HMPC: no monograph, neither as a medicinal product with recognised medicinal effect(well-established use) nor as a traditional medicinal product(traditional use); however, listed by the EMA in Poland and Hungary with traditional use.
ESCOP: not yet processed.
Commission E-monograph: for loss of appetite and prevention of age-related vascular changes.

No classification as traditional medicinal product in the sense of § 39a AMG.

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  • Biologically, the genus Allium is divided into two varieties, Var. cepa, the edible onion, and Var. ascalonicum Baker, the shallot. Other important vegetable species of the genus Allium are garlic, leek, chives and wild garlic as an intermediate and wild form. In naturopathy, the kitchen onion is traded as a universal remedy. Its essential oils have a strong antibacterial and disinfecting effect, antiphlogistic and pain-relieving.
  • All onions contain allicin, a sulphurous essential oil which is responsible for the natural antibiotic effect of the kitchen onion. The following ingredients have been proven: vitamin C (only raw), potassium, calcium and phosphorus, sodium and iron.
  • There is evidence that onions can reduce the risk of cancer.

Field of application/use
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  • Onion sachet: Onion sachets are used for earache. To do this, heat a large chopped onion in a pan, put it in a small bag or a large handkerchief and place it as a compress on the ear and/or behind the ear.
  • Onion slice: For insect bites (see below bee sting), a fresh onion slice applied helps. It is therefore advisable to take a small onion with you on hikes.
  • Onion porridge: For boils and abscesses, grind a raw onion with a hand blender, mix with water to make a porridge and place on the affected area.
  • The disinfecting effect of onions and onion juice is often used in naturopathy, e.g. for colds, against cough irritation, to ward off infections, for small wounds and for insect bites.
  • The improvement of scarring could be proven in a clinical study on 59 patients.
  • Alopecia areata

Onion extracts and their use in cosmetic preparations

  • Allium cepa bulb extract (INCI): extract from the bulbs of the kitchen onion. Cosmetic effect: skin caring
  • Alium cepa root extract (INCI): Extract from the roots of the onion. Cosmetic effect: antioxidant
  • Allium chinense bulb extract (INCI): extract from the bulbs of Allium chinense. Cosmetic effect: skin caring
  • Allium fistulosum root extract (INCI): Extract from the roots of the winter onion. Cosmetic effect: antioxidant
  • Allium fistulosum bulb extract (INCI): extract from the bulbs of the kitchen onion. Cosmetic effect: skin caring

Undesirable effects
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Despite continued use, food allergies to onions are rather rare (see below onion allergy). Cases of exertion-associated food allergy are described. The main cause was raw onions. In most cases the allergen is allicin. Occupationally exposed cooks and greengrocers may develop rhinitis and asthma as well as protein contact dermatitis. Cross-reactivity to other lily plants such as onions, asparagus or leeks does not usually exist. The diagnosis should be made by prick and i.c. with commercial extracts, scratch with native material, RAST. Occasionally contact eczema is observed on onions. In the case of hand eczema, the possibility of sensitisation through the kitchen onion should always be considered. Risk groups for contact allergies are cooks, housewives and vegetable sellers. The test is carried out with a 1% concentration of the aqueous or ethanolic extract or with expressed onion juice.

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  1. Ammon H et al (2014). Hunnius pharmaceutical dictionary. Walter de Gruyter GmbH Berlin/Boston pp 62-63.
  2. Draelos ZD et al (2008) The ability of onion extract gel to improve the cosmetic appearance of postsurgical scars. J Cosm Dermatol 7: 101-104
  5. Sharrquie et al (2002) Onion (Allium cepa L.), a new topical treatment for alopecia areata. J. Dermatol; 29: 343-346


Last updated on: 18.07.2021