Iodine, also known as iodine tincture, is a disinfectant solution of iodine and alcohol mixed together, in which the concentration of iodine inside is relatively high, about 2%-7%. The main component of alcohol is ethanol, which is 75% ethanol. Both iodine and alcohol can be used for disinfection at the skin, usually in places where the skin is intact and unbroken. In the past, it was very common to use both together during surgery. The area to be disinfected before surgery is wiped once with iodine and then twice with alcohol to remove the iodine. If the iodine is not removed, there is a risk that the iodine will cause pigmentation on the skin and may also cause an allergic reaction.