Essential Oils alone are concentrated. Base oils are used to extend and dilute the essences and act as a vehicle to use them. Bases can slow down the evaporation of the Essential Oil allowing us to have extended exposure to their fragrance and qualities. In addition to carrier (or base) oils, Essential Oils may be carried in honey, clay, sugar and water. Common carrier oils are Almond Oil, Jojoba Oil, Grape Seed Oil, Olive Oil, Sunflower Seed Oil.
A general rule is to dilute by adding 10 to 30 drops in one ounce of base oil.