Psoriderm Scalp Lotion Shampoo contains two active ingredients, distilled coal tar and lecithin. Coal tar has been used in skin conditions for hundreds of years, but it is still not fully understood how it works, mainly because it is made up of so many different compounds. It 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 the thickening and scaling of the skin and clears up psoriasis plaques. Coal tar may also work by breaking down keratin, a protein that forms part of the skin structure. This helps the skin cells shed from the treated area, thus reducing the thickening and scaling of the psoriasis plaques. Lecithin is a phospholipid that is included in this medicine to soften psoriasis scales and enhance the absorption of the coal tar into the skin cells. Psoriderm scalp lotion is used to treat psoriasis of the scalp. Please note that results may vary.