Exorex Lotion is a skin lotion (also known as cutaneous emulsion) for external use only. It contains coal tar solution which relieves and prevents itching and promotes the softening of the outer layer of skin. The tar acids in coal tar have been shown to have anti-bacterial properties. Exorex Lotion is for the treatment of psoriasis. Coal tar has mild antiseptic and anti-inflammatory effects, and relieves itching. It is also absorbed into the skin cells and is thought to inhibit DNA replication in these cells. This slows down cell division and stops the cells from multiplying excessively. In turn, this reduces thickening and scaling of the skin.