Chlorhexidine is a broad-spectrum, guanidino-containing antimicrobial agent (Figure S6) that is widely used as antiseptic. It was first approved in the U.S. in 1986 and is used for gingivitis and periodontitis. It is also used for the oropharyngeal sanitization to reduce the risk of ventilator-associated or hospital-acquired pneumonia. It is used as a skin disinfectant for preoperative skin preparation. It can also be used to disinfect hands, surface wounds, surgical tools, and surgical scrub, for both patients and healthcare workers [252,253,254,255].