Onions - Allium Cepa (Liliaceae)

Medicinal Use of Onion – Allium Cepa (Liliaceae)


Bulbous perennial growing to 3 ft (1 m). Has hollow stems and leaves, and white or purple flowers.

Habitat & Cultivation

Native to the northern hemisphere, onion has been cultivated in the Middle East for millennia. It is now grown worldwide as a vegetable.

Part Used



Onion contains a volatile oil with sulphur-containing compounds such as allicin (an antibiotic) and alliin, flavonoids, phenolic acids, and sterols.

History & Folklore

Authorities throughout the ancient world recommended onion for a variety of health problems. Bunches were hung on doors to ward off the plague in medieval Europe. Wild onion (A. sibiricum) was also used extensively by Native North Americans to treat stings and help relieve colds.

Medicinal Actions & Uses

Onion boasts a long list of medicinal actions—diuretic, antibiotic, anti-inflammatory, analgesic, expectorant, and anti-rheumatic. It is also beneficial to the circulation. Onions are taken the world over for colds, flu, and coughs, much like garlic (A. sativum). Onion offsets tendencies to angina, arteriosclerosis, and heart attack. It is also useful in preventing oral infection and tooth decay. The warmed juice can be dropped into the ear for earache, and baked onion is used as a poultice to drain pus from sores. Onion has a longstanding reputation as an aphrodisiac, and it is also used cosmetically to stimulate hair growth.

Related Species

In Chinese herbal medicine, the scallion (A. fistulosum) is given to encourage sweating, to unblock the nose, and to relieve bloating. It is also used to help drain boils and abscesses.