Benzalkonium chloride is a quaternary ammonium compound that functions as an antimicrobial agent, surfactant and preservative. It can be found in skincare products like hand sanitizers and disinfectants to help kill bacteria and germs. It may also appear in some cosmetic and personal care products as a preservative and surfactant to maintain product stability and improve texture and consistency. Its use in leave-on skincare products has caused concern because of the potential for skin irritation.