Sterilization, stehr uh luh ZAY shuhn, in medicine and bacteriology, means the killing of germs. Germ killing helps to prevent infection and the spread of disease. Doctors and dentists sterilize their tools before they touch the human body. The bandages and many of the medicines we buy are sterilized before they are packed. Sterilization has been practiced only since the late 1800's. The English surgeon Joseph Lister introduced antiseptic, germ-killing methods into surgery.