70% to 75% 70% to 75% ethanol is the best concentration for disinfection, which is often used for skin disinfection, medical equipment disinfection, environmental disinfection and so on. Ethanol can destroy the cell wall of bacteria and play a role in sterilization and disinfection. Excessive concentration of ethanol will make the protein on the surface of bacteria quickly solidify and form a hard film, which will prevent ethanol from entering the bacteria and affect the sterilization effect.