The term resident skin flora describes the physiological skin flora of humans and animals. This consists of various germs and microorganisms, such as Staphylococcus epidermidis, propioni– and corynebacteria. These microorganisms perform important functions, such as ensuring the correct balance of the resident germs or inhibiting the growth of foreign (non-resident) bacteria and fungi. Each part of the body has its own permanent colony. Roughly 80 per cent of a body’s resident skin flora is located on the outermost layer of the epidermis. Whenever a skin area is damaged, the germs in the skin flora can cause infections. The dual aims of surgical hand sanitation are to reduce transient germs, as well as reduce resident skin flora, so as to protect patients from infections caused by the surgeon’s skin flora during surgery.