Castor oil comes from the seeds of the Castor plant (Ricinus communis), native to India. The seeds are pressed to obtain the oil. Cold pressed is the ideal extraction method.
At this point, the main purpose of castor oil for me is as one of my base oils in my cosmetic line. It is one of the main oils used in my lipsticks, lip liners, and eye liners. However, as I study it more, I feel it may become something I use more frequently in some of my treatments.
It is also used in several other industries. The food industry uses it as a mold inhibitor. Castor oil is also used as an engine lubricant particularly in race cars and airplanes. The brand Castrol takes its name from the oil.
For health care, castor oil has long been used as a laxative and is known for aiding in relieving constipation. Castor oil is very high in ricinoleic acid which has anti-inflammatory properties. There are studies that show it has had some benefit in treating arthritis. There are also studies crediting castor oil with boosting your immune system in general. Further studies are needed, but the centuries years of use seem to support these qualities of the oil. It will be interesting to see what develops in the next few years of scientific studies.