Essential oils should not be consumed. Essential oils' chemicals can interact with your body in a variety of ways. Some plant chemicals are absorbed when applied to the skin. Certain application methods, such as applying with heat or to different areas of the body, are thought to improve absorption.
Inhaling essential oil aromas can stimulate areas of your limbic system, which is a part of your brain involved in emotions, behaviour, sense of smell, and long-term memory.
Surprisingly, the limbic system is heavily involved in memory formation. This helps to explain why familiar odours can elicit memories or emotions.