Let's review the course and what you will learn. 

It's important to have some basic knowledge of the structure and function of the skin to best understand how essential oils interact with the skin. 

Let's review essential oils as a natural ingredient and what that means in relation to its use in skin care and sensitivity. 

Though essential oils are excellent in skin care, it's beneficial to evaluate the different ways essential oils and their compounds are known to cause irritation and allergic reaction. We will also discuss the many ways this can be avoided. 

As final review we will look at other extractions similar to essential oils, and the quality of essential oils. We will also talk about two other issues, oxidation and photosensitization, that also effect allergic reactions and irritation of the skin.