A medical dressing is a pad or compress that is disinfected and sterilized. The purpose of a medical dressing is to promote the healing of wounds, which it does by covering the injury. People often confuse dressings with bandages, but a bandage is the part used to hold the dressing in place.
Although its main purpose is to help a wound heal, a medical dressing has a lot of uses. For bleeding wounds, it can stem the bleeding to speed up the clotting process and absorb the blood and any other fluid the wound may be secreting. Some dressings provide pain relief, either through the dressing's active chemicals and materials, or through placebo effect. A dressing can also be used to hide wounds, if one so wishes.