Chlorhexidine is a disinfectant and antiseptic used for skin disinfection before surgery and for sterilization of surgical instruments. It can be used to disinfect both the patient's skin and the hands of medical personnel. It is also used to clean wounds, prevent dental plaque, treat yeast infections in the mouth, and prevent blockage of urinary catheters. It is most commonly used as a liquid, and less commonly as a powder. Chlorhexidine is effective against a wide range of microorganisms, but it is ineffective against bacterial spores.