The onion (Allium cepa), is the most widely cultivated species of the genus Allium. Wide-ranging claims have been made for the effectiveness of onions against conditions ranging from the common cold to heart disease, diabetes, osteoporosis, and other diseases. They contain chemical compounds believed to have anti-inflammatory, anticholesterol, anticancer, and antioxidant properties, such as quercetin. Preliminary studies have shown increased consumption of onions reduces the risk of head and neck cancers. Onions may be beneficial for women, who are at increased risk for osteoporosis as they go through menopause, by destroying osteoclasts so they do not break down bone. For all varieties of onions, the more phenols and flavonoids they contain, the more reputed antioxidant and anticancer activity they provide. When tested against liver and colon cancer cells in laboratory studies, It was effective in inhibiting their growth.

• For hair fall, hair loss: Chop the onions first to get maximum juice out of it. You usually apply hot oil to open your scalp pores. But you cannot heat onion juice. So wrap a hot towel on your head half an hour before you apply the juice so that it gets absorbed easily.
• For damaged hair: Whip the onion juice with a bit of honey to make a hair gel. It will make the smell much more tolerable and it is unquestionable good for your hair.
• For dry scalp, dry hair: To add that add that lustre to the volume of your hair, you must try this hair pack once in a while. Remember the pulp that was left behind after extracted the onion juice? Mix it with coconut oil to make a gel like paste. Now add cup of beer to this. Beer along with onion gives your hair a naturally silky shine. The coconut oil is to give nutrition to the roots.
• For damaged hair: You need to soak a handful of finely chopped onion in a glassful of rum. Leave it overnight without refrigeration so that the juices can bleed into the rum and ferment a little. You can strain out the onion pieces and use the remaining concoction to massage your scalp. If you have made it in sufficient amount then you can rinse your hair with it.
• For sinusitis, colds: Two onions, extra-virgin olive oil and curry powder are all you need to treat this aliment. The onions should be sliced thinly and sautéed in 1 teaspoon of curry powder with two tablespoons of the virgin olive oil.
• For cough, nasal congestion: Boil an onion in a pot of water and let it simmer for twenty minutes. Drink a cup of this tea at least once a day.
• cough, flu, colds, infections, congestion: Chew on fresh onion.