Scientific Classification:

Kingdom Plantae
Unranked Angiosperms
Unranked Eudicots
Order Asparagales
Family Alliaceae
Genus Allium
Species A.cepa
Binomial name Allium cepa

Other Common Names:

The other name for onion is common onion.


Onions are perennials that are cultivated for food worldwide. There are many varieties. Most onion bulbs are white, yellow, or red. Onion has been used as a food source for almost as long as humans have been keeping written records.

Their usefulness has been discovered independently by many cultures on several continents. Onions are mentioned in ancient Egyptian writings and were known in ancient Greece. Onion has also been shown to contain antioxidants, which are compounds that protect the body against free radicals. The German Federal Health Agency's Commission E, established in 1978 to independently review and evaluate scientific literature and case studies pertaining to herb and plant medications, has approved onion as an antibacterial agent.


The common onion is a biennial garden plant, having a scape, which appears the second year, 2 to 4 feet high, being naked, smooth, straight, stout, swollen at the base, and fistulous, bearing at the top a round umbel of greenish-white flowers.Bulbing onions have cylindrical, hollow leaves and an enlarged bulb that develops at ground level. The roots come off the bottom of the bulb.

The flowers are produced in the second growing season in a rounded umbel which is a cluster with all flower stems originating from the same point on a stalk 2-4 ft tall. The umbels, about 2 inches in diameter and consisting of many small purplish flowers, are quite showy. It is less pungent to the taste than garlic, with some degree of sweetness, and a peculiar, well-known odour. Onion bulbs are of various shapes and sizes, usually globular, the layers being juicy.


The onion is a native plant of the northern hemisphere. Millennia ago, the onion were one of the first plants cultivated in the Middle East. The popularity of the onion is such that it is now grown as a major vegetable around the world.


Onion is a cultivated crop and it prefers light sandy and medium loamy soils and requires well-drained soil. The plant prefers acid, neutral and basic alkaline soils and can grow in very alkaline soil. It cannot grow in the shade. It requires moist soil. Regular garden watering is best. Onions may go dormant during extreme dry periods.


Early sowing of the seed can be made in February in a greenhouse to be planted out in late spring. The main sowing is made in March or April in an outdoor seedbed; this bed must be very well prepared. A sowing can also be made in an outdoor seedbed in August of winter hardy varieties .These over winter and provide an early crop of onion bulbs in June of the following year. Onion sets can be planted in March or April. Sets are produced by sowing seed rather thickly in an outdoor seedbed in May or June. The soil should not be too rich and the seedlings will not grow very large in their first year. The plants will produce a small bulb about 1 - 2cm in diameter, this is harvested in late summer, stored in a cool frost-free place over winter and then planted out in April. A proportion of the bulbs will run quickly to seed but most should grow on to produce good sized bulbs. If you replant mature onion bulbs or leave them in the ground after the tops have dried and withered, they will stay dormant for a "rest" period, and then start growing again. In their second growing season they will produce flowers and seeds, and then die.

Parts Used


The bulb is the commonly used parts of the onion for its commercial and medicinal purposes.

Flowering Season

The hermaphrodite flowers which are produced in the second growing season are in bloom from June through July.

Pests and Diseases

It is commonly affected by pests like onion root maggots, thrips, cutworms, pinkrot, neckrot, garlic mosaic and aster yellow.

Medicinal Applications


• Internally, onion has been recommended to treat colds, cough, bronchitis, whooping cough, asthma, and other respiratory problems.

• It is believed to help loosen congestion in the lungs and expand the airways.

• Circulation in the human body is also benefited by consuming the onion and related herbs.

• Onion is also used internally to relieve excess gas and calm an upset stomach. Onion is also thought to stimulate the appetite.

• It is also thought to help reduce arteriosclerosis by lowering blood cholesterol levels and preventing the formation of blood clots.

• Onion has been used to treat diabetes and is reputed to lower blood sugar levels.

• The aphrodisiac actions of the onion are also an ancient and longstanding reputation of the herb.

• It can be applied to wounds and stings on the skin, used to remove warts, used to stimulate hair growth, and even used to reduce unwanted skin blemishes. Warm onion juice dropped in the ear is said to help relieve earache.

• Hollands gin, in which Onions have been macerated, is given as a cure for gravel and dropsy.

Commercial Applications


• The plant juice can be used as a rust preventative on metals and as a polish for copper and glass.

• Onion based remedies are also believed to be cosmetically useful in stimulating hair growth in case of balding problems.

• The juice of the plant is used as a moth repellent and can also be rubbed onto the skin to repel insects.

• It is also used as a cosmetic to get rid of freckles.

• A yellow-brown dye is obtained from the skins of the bulbs.


According to the astro reports the onion bulb is under the dominion of the planet Mars.

Cultural and Religious Significance

The plant for today in the French Republican calendar is the onion. The onion is a plant with a long history and a lot of folklore. It is believed that the onion originated in the steppes of Asia and probably grew wild all over the world. They are first mentioned in Egypt where they were fed to workers on the pyramids, and depicted in paintings as offerings to the gods. In Greece, athletes consumed onions to balance the blood and in Rome, they were rubbed on the skin of gladiators. Perhaps they recognized their antibacterial qualities and thus protected themselves from infection.

Folklores and Myths

Onion seeds have been found in Egyptian tombs dated to 3200 BC, and some authorities believe the onion may have been one of the first vegetables domesticated by humans. The ancient Greek historian Herodotus, writes of nine tons of gold being spent to purchase enough onions to feed the builders of the pyramids - this suggests the immense popularity of this vegetable in Egypt of the pharaohs. The ancient Egyptians even offered the humble onion bulb as a sacrificial offering to their god, to the great amusement of the conquering Romans.

Thus not only was the onion widely used in the ancient world, but also highly valued by some societies. The onion had other uses during the later stages of the Middle Ages when the onion began to be used as a charm against evil spirits and the dangers of the plague - the strong smell of the herb was probably thought to influence and ward off spirits and disease. There are few myths about onion like to keep your automobile windshield from frosting at night, slice an onion and rub the windshield with the onion. The juice will keep it frost-free and also like to select your husband-to-be from among suitors, it is said that if the name of each suitor is written on an onion and then placed in a cool dark storeroom, the first onion that sprouts will be the man she should marry.

Onions were also used as protection charms. In some parts of the United States, black folks carried a red onion in the left hand or left pocket to ward off disease. In South Carolina, a necklace of small crushed onions was put around the neck of a child with diphtheria to overpower the disease. New England settlers hung a string of onions over the door to absorb germs and prevent them from harming the residents. These onions could never be eaten. The Shinnecock Indians of Long Island would put an onion in the sick room to draw the fever out; once having done so it would turn black.