Castor was one of the first medicinal plants known to humans. The Egyptians added Castor oil to beer and drank as a purgative for cleansing their system. The oil has been applied to the breast of nursing mothers to increase milk, relieve inflammation, soften the mammary glands, and as a lactagogue. Castor oil is also good for blackheads and to care for the hair and scalp. It has analgesic and anti-inflammatory properties.