Onions can be used to soothe stings and bug bites. All you need to do is place an onion slice on your sting or bite. The anti inflammatory properties of onion help in reducing the burn, itchiness and swelling caused by insect and bug bites. Onions are a very good source of biotin. They are also a good source of manganese, vitamin B6, copper, vitamin C, dietary fiber, phosphorus, potassium, folate, and vitamin B1.