Onions are known to be rich in biotin. Most of the flavonoids which are known as anti-oxidants are concentrated more in the outer layers, so when you peel off the layers, you should remove as little as possible.
Onion can fill your kitchen with a thick spicy aroma. It is a common base vegetable in most Indian dishes, thanks to the wonderful flavor that it adds to any dish.

If a piece of onion is inhaled, it can slow down or stop nose bleeding.
Those who have sleeping disorders or insomnia can have a good night sleep if they have an onion every day.
Onions are known to have antiseptic, antimicrobial and antibiotic properties which help you to get rid of infections.
Onions are high in sulphur, vitamin B6 and B9. It has high quantities of water and naturally low in fat. It is high in phytochemical compounds.
Onions are known to contain manganese, copper, Vitamin B6, Vitamin C, Folic acid, Amino acid and dietary fibers along with phosphorus, folate and copper.