What are antibiotics? What preventions must be taken while taking antibiotics?

Antibiotics, also known as antibacterials, are medications that destroy or slow down the growth of bacteria. They include a range of powerful drugs and are used to treat diseases caused by bacteria. Antibiotics cannot treat viral infections, such as cold, flu, and most coughs.
Precautions to be taken while using antibiotics are:
- Antibiotics should be taken under the supervision of a well qualified doctor.
- Course intake of antibiotics should be completed as prescribed by the doctor.
- Do not take antibiotics prescribed for someone else. 
-Taking antibiotics too often or for the wrong reasons can change bacteria so much that antibiotics don't work against them. This is called bacterial resistance or antibiotic resistance.