Onion oil is a member of the Amaryllidaceae family. This oil has a strong, unpleasant, sulphurous odour that is not recommended for aromatherapy. It is classed as a middle note and doesn't normally blend well with other oils.
Onion boasts decongestant and expectorant abilities. Even though it can be effective in skincare formulations due to its anti-viral benefits, it is more commonly used as fishing bait due to it's less than pleasant aroma.
Essential oils can be applied topically once diluted with a carrier oil. They are widely used in cosmetic goods and handmade crafts.