Base oils are used in aromatherapy and come from the fatty portion of a plant, such as seeds, grains, fruits. They can be used for body massage, skin treatment or as a hair tonic. Base oils can also be mixed with essential oils to dilute their highly concentrated form. Each base- or carrier- oil offers a different combination of properties and characteristics. The choice of base oil depends on the desired effect being sought. Their effect is beneficial for moisturizing and skin care.