An abscess is a pus-filled sore, usually caused by a bacterial infection. It results from the body's defensive reaction to foreign material. Abscesses are often found in the soft tissue under the skin, such as the armpit or the groin. However, they may develop in any organ, and are commonly found in the breast and gums. Abscesses are far more serious and call for more specific treatment if they are located in deep organs such as the lung, liver, or brain.

Most abscesses are caused by an infection. In response to an invading germ, white blood cells gather at the infected site and begin producing chemicals called enzymes that attack the germ. These enzymes act like acid, killing the germs and breaking them down into small pieces to be picked up by the circulation and eliminated from the body. These chemicals also digest body tissues. In most cases...