Jamaican black castor oil is an unrefined castor oil that is so-called because the oil is manufactured in Jamaica and has a high ash content, which is what gives it a dark black color. Black castor oil was first made in Jamaica hundreds of years ago and the Jamaicans have been reaping its health benefits ever since.
Unlike refined castor oil, Jamaican black castor oil is made by roasting organic castor seeds, grinding them, and then boiling them in order to extract the black oil from the seeds. Roasting the seeds for long periods of time increases the ash content of the oil, which increases the potency of the finished product. You can judge the quality and ash content of black castor oil by how dark it is.
So what is Jamican black castor oil used for? It is said to be especially beneficial for the hair and skin. It can also be used as a massage oil and reportedly helps soothe sore muscles and aching joints as well as arthritis pain. It is also said to reduce breast tenderness associated with hormonal fluctuations and is reported to prevent cysts and lumps in the breasts when applied topically.