If you have a cut on your skin, you cannot apply iodine and red salve together, as both will produce harmful substances that will affect your health. The iodine in iodine can denature the proteins of disease-causing microorganisms and also kill bacterial spores, which has a strong effect on killing disease-causing microorganisms that cause infections in the body. Red saline, also known as red mercury, is an organic compound of mercury and bromine, in which the dissociated mercury ions will combine with the proteins of disease-causing microorganisms and precipitate the proteins, which has a good antibacterial and bactericidal effect, thus achieving the purpose of disinfection. However, in the case of skin scratches, iodine and red salve should not be applied together, nor should they be used successively in the same area. This is because the iodine in iodine can react chemically with the mercury ions in red salve to produce mercury iodide. This is a highly toxic substance that can have a strong irritating effect on skin mucous membranes and other tissues. When the content is too high, it may cause further damage to the skin, mucous membrane ulcers, and even symptoms such as fatigue, headache, and a drop in body temperature, and in severe cases, it can also cause mercury poisoning and heart failure. If a pregnant woman accidentally uses both at the same time, it may lead to fetal malformation. It is important to note that when the skin is scratched, if the wound is small, you can first wipe the wound with a disinfectant, such as iodine, iodophor, alcohol or red saline, etc., should be handled from the wound outward, and do not use the cotton ball wiped around the skin to wipe the wound again; if the wound is large, or the surrounding conditions do not allow, you can use pure water or saline to rinse the wound, and then put on a band-aid or gauze, promptly Seek medical treatment.