The oil obtained from the seeds of the castor oil plant Ricinus communis is one of the oldest drugs known to man. Castor oil is known primarily as an effective laxative; however, it was also used in ancient times with pregnant women to induce labor. Aside from getting rid of acne, castor oil also helps detoxify the skin. It helps break up the oils that clog glands and pores on the face. Only now, have scientists at the Max Planck Institute for Heart and Lung Research succeeded in unravelling the mysteries of the action mechanism. Ricinoleic acid released from the oil in the intestine, is responsible for the analgesic and anti-inflammatory effects. It was discovered, that G protein-coupled receptors, a large group of receptors in the body involved primarily in transmitting signals in cells. Hundreds of receptors were systematically turned off, and then the reaction of the cells to ricinoleic acid was tested. Ultimately, was succeeded identified the key receptor with the name EP3. There was concluded that after being released from the castor oil, the ricinoleic acid is first of all absorbed by the body via the intestinal mucosa; the EP3 receptor then becomes active on the muscle cells of the intestine and uterus, which in turn stimulates intestinal activity.