Onion

Onion, Herbaceous biennial plant (Allium cepa) of the family Alliaceae, probably native to southwestern Asia but now grown worldwide, and its edible bulb. Among the hardiest and oldest garden vegetable plants, onions bear a cluster of small, greenish white flowers on one or more leafless stalks.

Onion contains chemicals that seem to reduce swelling and lung tightness related to asthma. It also contains chemicals that seem to reduce cholesterol and lower blood sugar. People use onion to prevent scarring. It is also used for obesity, hair loss, asthma, insomnia, high blood pressure.