Castor oil is a vegetable oil that is extracted from the seeds of the castor plant (Ricinus communis). It is a pale yellow to brownish-yellow liquid with a distinct odor and taste. It is often used as a lubricant, as an additive in cosmetics and soaps, and as a remedy for constipation and other digestive issues. Castor oil has also been used to treat skin conditions such as acne and psoriasis, and to stimulate hair growth.