Polytar shampoo contains tar blend, which consists of pine tar, cade oil, coal tar solution and arachis oil extract of coal tar. 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. 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. 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 thickening and scaling. Polytar shampoo is used to treat scaly, itchy skin conditions affecting the scalp, such as psoriasis, seborrhoeic dermatitis or dandruff.