Each weekday, Marshall Brain and the HowStuffWorks Staff answer questions in the Question of the Day section of HowStuffWorks. The Question Archive lets you view hundreds of questions and answers. Click here to ask a question . Answer Antibiotics work to kill bacteria.
Bacteria are single-cell organisms.
If bacteria make it past our immune systems and start reproducing inside our bodies, they cause disease. The reason we want to kill the bacteria is to eliminate the disease. Certain bacteria produce chemicals that damage or disable parts of our bodies. In an ear infection, for example, bacteria have gotten into the inner ear. The body is working to fight the bacteria, but the immune system's natural processes produce inflammation.