WOUND infections have been a major problem since surgery began and, despite improved techniques to avoid and combat them, they remain an important complication of surgery. This article discusses the stages in the prevention of wound contamination. The basic principle of aseptic technique is that microbiological contamination and subsequent infection cannot occur if microorganisms are totally excluded from a wound. The reality of aseptic technique is a working set of complementary and independent technologies and operating room protocols designed to prevent or minimise microbiological contamination of the surgical wound. All items that come into contact with the wound should be sterile. If an item cannot be made sterile, it is rendered surgically clean by washing with antiseptics or disinfectants which destroy most, but not all, microorganisms.