Castor oil is the oil made from the seed of the castor plant (Ricinus communis L.), and is a popular oil with a multitude of uses. It is a carrier oil, used for diluting essential oils. It can be used on the skin, as a massage oil or as an emulsifier in cosmetics. Castor oil contains antioxidants, which can help reduce redness, swelling and discomfort in the skin. It can also be used on the hair, as a hair mask and to assist in treating dandruff. This oil is not for consumption, and should be avoided by those with nut allergies. Store your castor oil in a cool place out of direct sunlight.