Carrier oil, also known as base oil or vegetable oil are derived from the fatty portion of a plant. Particularly there seeds, kernels or nuts. The term carrier oil is derived from their capacity to carry essential oils onto the skin. If applied to the skin undiluted, essential oils, absolutes and other concentrated aromatics can cause severe irritation to some individuals. This is why carrier oils are used to dilute concentrated aromatics prior to topical applications.
Each carrier oil offers a different combination of therapeutic properties and characteristics. The choice of carrier oil can depend on the color, viscosity, shelf life, aroma and/or the therapeutic benefits being sought. Vegetable (carrier) oils do not contain a concentrated, pungent aroma, unlike essential oils. Though some, such as olive oil have a mild distinctive smell.