A technique to produce a germ-free environment to protect patients from infection. It is used for any procedure that might introduce infection into the body, and is essential for all surgery – even minor procedures. Asepsis is achieved by ensuring that all people who come into contact with the patient scrub their hands and wear sterilised gowns with disposable masks and gloves. Operating-theatre air and equipment must also be clean. An aseptic technique is also necessary when caring for patients whose immune system (see IMMUNITY) is suppressed: one example is LEUKAEMIA, the treatment of which affects the immune system. Asepsis is aimed at preventing infection; antisepsis is the use of chemicals to destroy germs already on the body or in a wound (see ANTISEPTICS).