In aromatherapy, carrier oils are vegetable oils that are used as a base to dilute essential oils before they are applied to the skin. Carrier oils are used because most essential oils are thought to be too concentrated to apply directly to the skin. They're called carrier oils because they carry the scent of the essential oil to the skin where it can be absorbed.
Some of the more popular carrier oils are sweet almond oil, grapeseed oil, apricot kernel oil, coconut oil and avocado oil. Most aromatherapists prefer to use carrier oils that are labeled "cold-pressed," which means they are processed without heat. Unlike essential oils, carrier oils often have a light or no aroma and don't evaporate.
One of the most popular uses of carrier oils is for aromatherapy massage.