I think most people are familiar with this method of enjoying an essential oil. Either put a few drops of oil in a diffuser, or inhale from the bottle or apply to hands and cup over nose and inhale.
Aromatherapy is the best way to use oils to change mood and emotions, as our sense of smell is closely tied to the area of the brain which controls emotions and long term memory.
Inhaling an essential oil can also powerfully affect the respiratory system. It is great for opening the airways and addressing symptoms of allergies.
The great benefit of topical application is that therapeutic effects can occur both at the site of application and throughout the body. When an essential oil is applied to the skin it will be in the bloodstream within minutes. Molecules of that oil can then be found in every cell in the body within 20 minutes, so the benefits of topical application of any oil are widespread.
Topical application of an oil can be hugely helpful for skin conditions and muscular and joint pain.
Internal application of oils refers to consuming them. I think this is the application that most people are unaware of.
Only the purest of oils should be taken internally. There should be very clear directions from the producer of the oil about whether it may be used in this way. Some of the digestion supporting oils have a wonderfully therapeutic effect when taken internally.
Oils can be taken sublingually, or in water, or used in cooking or taken as supplements by making up your own vegetable capsule diluted with a carrier oil, such as Fractionated Coconut Oil.