Family: Liliaceae

Bengali/Vernacular Name: Piaj.

English Name: Onion.

Description of the Plant:

A bulbous herb. Leaves linear, cylindrical hollow in 2 rows. Flowers small, in globular many flowered umbel at the end of a hollow, inflated scape, taller than leaves.

Using Information:

Bulb is tonic, stimulant, expectorant, stomachic, aphrodisiac, diuretic, emmenagogue and emetic; used in cough, catarrh, asthma, rheumatism, colic and insect bites. They are useful in body pain, scabies, earache, tumours, bleeding piles, epistaxis, ophthalmia, flatulency and dysentery. It is used externally for scorpion-stings and to allay irritation in skin diseases. It is given internally in bronchitis, liver complaints, dysmenorrhoea, vertigo and migraine.

Regular use of onion (50g/day) reduces insulin requirement of a diabetic patient from 40 to 20 units a day. Continuous consumption of onion for 5 months (80g/day) decreased serum cholesterol below normal in healthy human. It also checks rise in serum triglycerides, ß-lipoproteins and phospholipids and increase clotting time (Asolkar et al., 1992).


Chemical Constituents:

Principal constituent of onion is an essential oil containing various sulphur compounds such as mono-, di-, tri-, and tetra-sulphides, thiols and thiophene derivatives. Onion also contains carbohydrates, proteins, amino acids, polyphenols, quercetin, kaempferol, vitamin B and C, a saponin, ß-amyrin, sterols, phenolic acids and minerals. Besides these a large number of cyaniding glycosides have been isolated from the bulb. Prostaglandins have been detected in the bulb and leaves of onion. Dry brown outer scale contains quercetin, and other flavanoid, sterols and phenolic compounds. Scales also contain catechol and protocatechuic acid (Ghani, 2003). Diosgenin has been isolated from flowers and bulb (Rastogi & Mehrotra, 1993).


Cultivated in most of the districts of Bangladesh.