Injection tracking marks in drug addict. View of the arm of a heroin addict, showing tracking marks due to intravenous drug abuse. The veins show bruising due to multiple injections; track marks from needle punctures are visible at lower frame. Heroin is the substance of abuse, a white narcotic drug (like morphine) which is dissolved in water before being injected. A makeshift tourniquet is used to dilate the superficial veins and provide a better target for the needle to 'hit'. Intravenous drug abusers risk the physical and psychological consequences of addiction, including the risk of needle infection.