Being a transparent viscous liquid, Castor oil has the little symplectic taste. Using castor oil can treat the dry knot, itching boils and burns. Its inner elements contain Ca, Fe, Si, Al, Cu, Mg, Zn and so on. It can be used to the clean the intestines and stomach for the intestinal dry constipation. As we know, the black circles under the eyes are always caused by the not good circulation of the body, staying up late at night or drinking too much the night before. The main role of castor oil for the black circles under the eyes is to clean the stomach and intestine which will make the blood circulation go on well. Thus, the melanin will be released and the black circles under the eyes will be disappeared. If you have the black circles under the eyes, you could have a try of using the castor oil.