Vegetable oils are used to dilute and distribute or "carry" a plant's essential oils. Although essential oils don't spoil, some vegetable oils do. To insure quality, add a bit of vitamin E to your blends as a natural preservative. Common carrier oils include almond, avocado, grapeseed, hazelnut, jojoba, olive and sesame oils.
Organic liquids in which essential oils can disperse and are used to dilute essential oils and, in many cases can assist application. Some carrier oils have their own therapeutic action.
When oils such as sweet almond, grapeseed,evening primrose, aloe vera, or avocado are mixed with pure essential oils they are called carrier oils. Each of these oils, having their own properties and grades, can be used for specific purposes.