WHEN you’re down sick with a particularly nasty bout of flu, or cough (of the phlegmy kind), the doctor is more likely to prescribe antibiotics as a form of treatment. One thing to know is that antibiotics are given as treatment for infections caused by bacteria. They are not effective against viruses. Antibiotics work by affecting things that bacterial cells have but human cells don’t.
For example, human cells do not have cell walls, while many types of bacteria do. The antibiotic penicillin works by keeping a bacterium from building a cell wall. Some antibiotics dissolve the membrane of just bacterial cells. Others affect protein-building or DNA-copying machinery that is specific to bacteria. The problem is that antibiotics not only kill harmful bacteria, but also friendly bacteria. This is why one has to weigh the pros and cons of taking antibiotics.