Alcohol is the ethanol in chemical reagents, and the concentration of alcohol commonly used in clinical practice is 75%. 75% alcohol is a relatively good sterilizing and disinfecting agent with good efficacy. Its mechanism of action is to denature bacterial proteins, reduce bacterial activity, and kill bacteria. It is commonly used clinically for wound disinfection and post-operative skin disinfection. Alcohol can cause severe pain when used to disinfect wounds and post-operative incisions, and care should be taken. Generally, alcohol is not harmful to human skin, but some people are allergic to alcohol, which can cause shock in severe cases. Alcohol can also be used to cool the body surface of patients with high fever, and it can be used to disinfect metal instruments when it burns. Alcohol is a volatile liquid, flammable and explosive, so care should be taken to store it properly.