If only 95% alcohol is available, 100 ml of 95% alcohol plus 26.67 ml of distilled water can be selected to match the concentration of 75% alcohol. Alcohol has a killing effect on pathogenic microorganisms, and there are two main mechanisms for killing, the coagulation effect of alcohol on pathogenic microorganisms and the penetration effect, which can effectively kill pathogenic microorganisms. The alcohol used for disinfection in hospitals is 75% alcohol, 95% alcohol coagulation effect is stronger, but the penetration effect is weaker, often some pathogenic microorganisms can not be completely killed. And 75% alcohol has the best coagulation and penetration effect, so it is very effective in the process of sterilization and killing. Content source: Dr. You Lai